Pregnancy Calculator

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Part of:The Complete Pregnancy & Women’s Health Guide 2026: Due Dates, Ovulation, Cycles & Prenatal Care

Professional review pending. Pregnancy Calculator has passed formula and automated QA checks, but no independently verified clinician is currently attributed. Content updated June 21, 2026. Review process

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Pregnancy Calculator

Calculate your due date, track your pregnancy progress, and discover important milestones throughout your journey.

📅 Calculate Due Date

Calculation Method

First Day of Last Period

Most common method - uses Naegele's rule (LMP + 280 days)

🤰

Enter your details

Results will appear here after calculation

Estimated due date (EDD) is calculated using Naegele's rule: add 280 days (40 weeks) to the first day of the last menstrual period (LMP). Pregnancy is divided into three trimesters: T1 (weeks 1–13, organogenesis, highest miscarriage risk), T2 (weeks 14–27, rapid fetal growth, anatomy scan at 18–22 weeks), T3 (weeks 28–40, lung maturation, positioning for birth). Gestational age is measured from LMP; fetal age is ~2 weeks less. Full-term: 39–40 weeks (ACOG); premature: <37 weeks; post-term: ≥42 weeks. First-trimester ultrasound (crown-rump length) is accurate to ±5–7 days.

Understanding Pregnancy & Due Date Calculation

Evidence-based obstetric science since 1756

280

Days average pregnancy

3

Trimesters

40

Weeks gestational

1756

Year Naegele's Rule established

🗓️ How Due Date Calculation Works

A due date, formally called the Estimated Date of Delivery (EDD) or Estimated Date of Confinement (EDC), marks the end of an average full-term pregnancy of 40 weeks (280 days) counted from the first day of the last menstrual period (LMP). The 40-week framework exists because most women ovulate around day 14 of their cycle, so the true fertilization window is approximately 2 weeks after the LMP begins.

In clinical practice, gestational age is measured from LMP even though the embryo is actually about 2 weeks younger than the gestational age suggests. This convention was standardized long before reliable conception-date testing was possible and remains universal today.

Naegele's Rule

The most widely used method for calculating due dates is Naegele's Rule, formulated by German obstetrician Franz Karl Naegele in 1756. The formula is elegantly simple:

Due Date = LMP + 280 days

Equivalently: LMP + 9 calendar months + 7 days

Example: LMP = January 1 → Due Date = October 8

LMP vs. Conception Date

🩸 LMP Method

• Counts from the first day of last period
• Assumes a regular 28-day cycle
• Most commonly used in clinical settings
• Ovulation assumed at day 14
• Gestational age = fetal age + 2 weeks
• Less precise for irregular cycles

🥚 Conception Date

• Counts from known fertilization date
• Adds 266 days (38 weeks)
• More accurate when date is confirmed
• Often used for IVF pregnancies
• Fetal age = gestational age − 2 weeks
• Requires reliable ovulation tracking

Clinical Note: First-trimester ultrasound (before 14 weeks) is considered the gold standard for dating accuracy, achieving a margin of error of ±3–5 days. After the first trimester, accuracy decreases and an LMP-based date is generally not revised.

📅 Pregnancy Timeline by Week

Week	Trimester	Key Milestone	Baby Size Reference
W4	1st	Embryo implants in uterine wall; neural tube begins forming	Poppy seed (~2 mm)
W8	1st	Heart beating; limb buds present; all major organs forming	Raspberry (~1.6 cm)
W12	1st	Nuchal translucency scan; all organs formed; miscarriage risk drops sharply	Lime (~5.4 cm)
W16	2nd	Gender often visible on ultrasound; baby makes facial expressions	Avocado (~11.6 cm)
W20	2nd	Anatomy scan; halfway point; many mothers first feel kicks	Banana (~25 cm)
W24	2nd	Viability threshold; lungs developing; baby responds to sound	Corn cob (~30 cm)
W28	3rd	Eyes open; REM sleep cycles; glucose tolerance screening	Eggplant (~37 cm)
W32	3rd	Rapid weight gain; lungs nearly mature; baby may turn head-down	Butternut squash (~42 cm)
W36	3rd	Baby drops into pelvis (lightening); cervix may begin softening	Honeydew melon (~47 cm)
W40	3rd	Estimated due date; fully developed; average weight ~3.4 kg / 7.5 lb	Small pumpkin (~51 cm)

🏥 Prenatal Care Schedule

Week Range	Visit Frequency	Tests & Screenings
Wk 4–8	Initial booking visit	Blood type, Rh factor, CBC, rubella immunity, STI screening, urine culture, genetic counseling referral
Wk 8–13	Once	Nuchal translucency ultrasound; cell-free DNA / NIPT (optional); chorionic villus sampling if indicated
Wk 14–27	Every 4 weeks	Anatomy scan at 18–22 weeks; AFP/quad screen at 15–20 weeks; amniocentesis if indicated
Wk 28–35	Every 2 weeks	Glucose challenge test at 24–28 weeks; Tdap vaccine at 27–36 weeks; RhoGAM for Rh-negative patients
Wk 36–40	Weekly	Group B Strep (GBS) culture at 35–37 weeks; fetal position check; cervical exam; biophysical profile if post-term

⚖️ Pregnancy Weight Gain Guidelines

Based on the 2009 Institute of Medicine (IOM) guidelines, adopted by ACOG.

Pre-pregnancy BMI	Category	Total Recommended Gain	Weekly Gain (2nd–3rd Trimester)
< 18.5	Underweight	12.5–18 kg (28–40 lb)	~0.5 kg / ~1 lb
18.5–24.9	Normal weight	11.5–16 kg (25–35 lb)	~0.4 kg / ~1 lb
25.0–29.9	Overweight	7–11.5 kg (15–25 lb)	~0.3 kg / ~0.6 lb
≥ 30.0	Obese	5–9 kg (11–20 lb)	~0.2 kg / ~0.5 lb
Any (twins)	Twin pregnancy	17–25 kg (37–54 lb)	~0.7 kg / ~1.5 lb

* Consult your healthcare provider for personalized recommendations.

📜 History of Pregnancy Dating

1756

Naegele's Rule formulated

Franz Karl Naegele publishes his due-date calculation method (LMP + 280 days), establishing the framework still used worldwide today.

1827

Egg cell discovered

Karl Ernst von Baer identifies the human ovum, revolutionizing understanding of fertilization and conception timing in mammals.

1950s

Obstetric ultrasound begins

Ian Donald pioneers obstetric ultrasound in Glasgow, offering real-time fetal imaging and a new, more accurate route to dating gestational age.

1978

First IVF birth

Louise Brown is born via in vitro fertilization, bringing precise date-of-conception knowledge and new due-date calculation methods for assisted reproduction.

1990s

Prenatal genetic testing advances

First-trimester combined screening and amniocentesis become routine, enabling chromosomal analysis alongside gestational age confirmation.

2000s

3D/4D ultrasound era

Three-dimensional and real-time 4D ultrasound imaging bring detailed anatomical views, improving fetal growth assessment and anomaly detection.

🎯 How Accurate Is Your Due Date?

LMP Method

Assumes a perfectly regular 28-day cycle with ovulation on day 14. Studies show accuracy within ±2 weeks in most regular-cycle pregnancies.

Margin: ±10–14 days

1st-Trimester Ultrasound

Crown-rump length measurement before 14 weeks is the most precise dating tool available in clinical practice.

Margin: ±3–5 days

2nd/3rd Trimester Ultrasound

Later scans assess head circumference, femur length, and abdominal circumference. Normal biological variation increases the error window.

Margin: ±2–3 weeks

Why Babies Don't Arrive on the Due Date

Only about 4–5% of babies are born exactly on their estimated due date. Natural labor is triggered by a complex cascade of hormonal signals from both baby and mother, with biological variability spanning several weeks. A term birth is defined as 37–42 weeks gestation. Babies born between 37 and 41 weeks and 6 days are considered "term" without medical concern about gestational age alone.

🔬 Research & Clinical Guidelines

ACOG Practice Bulletin

Methods for Estimating the Due Date

ACOG recommends ultrasound in the first trimester as the gold standard for gestational age assignment when discordant by more than 5 days from LMP-based estimates.

ACOG Committee Opinion No. 700 →

British Medical Journal

Distribution of Gestational Length at Birth

Multinational BMJ research shows spontaneous births cluster between 38 and 42 weeks, with the median at 39.5 weeks, reinforcing that 40-week due dates are estimates, not targets.

Morken et al., BMJ Open, 2014

WHO Guidelines

WHO Antenatal Care Recommendations

The World Health Organization recommends a minimum of 8 antenatal care contacts for a positive pregnancy experience, with early booking before 12 weeks whenever possible.

WHO ANC Model 2016 →

💡 Pregnancy Myths vs. Facts

❌

Myth

Your due date is an exact prediction of when your baby will be born.

✅

Fact

Only 4–5% of babies are born on their due date. Most arrive within 2 weeks before or after. The due date is the midpoint of a normal distribution of labor onset, not a deadline.

❌

Myth

Morning sickness only happens in the morning.

✅

Fact

Despite the name, nausea and vomiting can happen at any time of day or night. About 80% of pregnant women experience nausea, and for many it is persistent throughout the day, especially in the first trimester.

❌

Myth

You need to "eat for two" during pregnancy.

✅

Fact

You only need an extra ~300 calories per day in the second and third trimesters — roughly equivalent to a healthy snack, not a full additional meal. Excessive caloric intake increases gestational weight gain risks.

❌

Myth

Heartburn during pregnancy means your baby will have lots of hair.

✅

Fact

While one small Johns Hopkins study found a weak correlation, heartburn is overwhelmingly caused by progesterone relaxing the lower esophageal sphincter and the growing uterus putting upward pressure on the stomach.

❌

Myth

Exercise is dangerous during pregnancy.

✅

Fact

For low-risk pregnancies, ACOG actively recommends 150 minutes of moderate-intensity aerobic activity per week. Exercise reduces risk of gestational diabetes, preeclampsia, excessive weight gain, and cesarean delivery.

❌

Myth

If the fetal heartbeat is fast, it's a girl; slow means a boy.

✅

Fact

No scientific evidence supports fetal heart rate as a reliable sex predictor. The average fetal heart rate is 120–160 bpm in both sexes, varying with gestational age and activity level rather than sex.

❓ Frequently Asked Questions

How accurate is my estimated due date?▼

Due dates calculated from LMP are accurate within ±2 weeks for women with regular 28-day cycles. First-trimester ultrasound narrows this to ±3–5 days. Only about 4–5% of babies are born on their exact due date; the vast majority arrive somewhere within the 37–42 week window considered normal term delivery.

What is the difference between gestational age and fetal age?▼

Gestational age is counted from the first day of your last menstrual period (LMP). Fetal age (also called embryonic or conceptional age) counts from actual fertilization, which typically occurs around 2 weeks after LMP. A 12-week gestational age pregnancy therefore contains a 10-week-old fetus. All standard pregnancy charts and developmental milestones use gestational age.

How is the due date calculated for IVF pregnancies?▼

For IVF, the due date is based on the embryo transfer date and embryo stage. A Day-5 blastocyst transfer means the due date is 261 days after transfer (266 days from conception minus 5 days of embryo age). A Day-3 transfer gives a due date 263 days after transfer. IVF dating is typically more precise than LMP-based calculations because the exact fertilization date is known.

What counts as early, late, or post-term birth?▼

Early preterm is before 34 weeks. Late preterm is 34–36 weeks 6 days. Early term is 37–38 weeks 6 days. Full term is 39–40 weeks 6 days. Late term is 41–41 weeks 6 days. Post-term is 42 weeks or beyond. Induction or closer monitoring discussions typically begin at 41 weeks in most clinical guidelines.

When can I feel my baby move for the first time?▼

First-time mothers (primigravida) typically feel fetal movement called "quickening" between 18–25 weeks. Experienced mothers (multigravida) may notice it earlier, around 16–18 weeks, because they recognize the subtle sensation. Movement should become regular and consistent by 28 weeks. Absent movement after 28 weeks should be reported to a provider promptly.

What is the Group B Strep (GBS) test and when is it done?▼

Group B Streptococcus is bacteria that naturally colonizes the intestines and vagina of about 25% of healthy women without causing symptoms. During delivery it can be transmitted to the baby and cause serious neonatal infection. A vaginal/rectal swab is performed at 35–37 weeks. GBS-positive mothers receive intravenous antibiotics (usually penicillin) during labor to protect the newborn.

Can my due date change after it is first set?▼

Yes. If a first-trimester ultrasound (before 14 weeks) shows a crown-rump length inconsistent with LMP by 5 or more days, ACOG guidelines recommend officially revising the due date to match the ultrasound measurement. After the first trimester, due dates are generally not changed even if later scans suggest different measurements due to natural variability in fetal growth.

What is a biophysical profile (BPP) and when is it ordered?▼

A biophysical profile evaluates fetal well-being using five measures: fetal breathing movements, gross body movement, fetal tone, amniotic fluid volume index (AFI), and a non-stress test (NST). Each component scores 0 or 2 for a total out of 10; a score of 8–10 is normal. BPPs are typically ordered after 32 weeks in high-risk pregnancies, post-term gestations, or when the non-stress test is non-reactive.

What is the difference between a miscarriage and a stillbirth?▼

A miscarriage is pregnancy loss before 20 weeks of gestation; it occurs in approximately 10–20% of known pregnancies, with the vast majority happening in the first trimester due to chromosomal abnormalities. A stillbirth is defined as fetal death at or after 20 weeks. In the United States, stillbirth occurs in approximately 1 in every 160 deliveries; causes include placental insufficiency, umbilical cord accidents, infection, and fetal anomalies.

How is gestational age determined if I do not know my LMP?▼

If a woman cannot recall her last menstrual period or has highly irregular cycles, first-trimester ultrasound is used exclusively for dating. Crown-rump length (CRL) measured between 6 and 13 weeks is the most reliable single dating method, with a precision of ±3–5 days. Outside this window, biometric measurements of the fetal head, abdomen, and femur are averaged to estimate gestational age.

What prenatal vitamins and nutrients are most important?▼

Folic acid (400–800 µg/day begun before conception and continued through the first trimester) is essential to prevent neural tube defects. A complete prenatal vitamin should also contain iron (27 mg), calcium (1,000 mg), vitamin D (600 IU), iodine (150 µg), and DHA (200–300 mg for brain development). Choline (450 mg/day) is increasingly recognized as important for fetal brain development and is often under-supplemented.

What is preeclampsia and how is it monitored?▼

Preeclampsia is a pregnancy complication characterized by new-onset hypertension (≥140/90 mmHg) and signs of organ damage — most commonly proteinuria — arising after 20 weeks. It affects 5–8% of pregnancies. Risk factors include first pregnancy, multiple gestation, obesity, chronic hypertension, diabetes, and autoimmune disorders. Blood pressure and urine protein are checked at every prenatal visit. Low-dose aspirin (81 mg/day) from 12–28 weeks is now recommended for women with moderate-to-high risk factors.

📋 References & Further Reading

• ACOG Committee Opinion No. 700: Methods for Estimating the Due Date (2017). American College of Obstetricians and Gynecologists.
• Naegele, F.K. (1756). Erfahrungen und Abhandlungen aus dem Gebiethe der Krankheiten des weiblichen Geschlechts. Mannheim.
• Morken N-H, et al. Distribution of gestational length in a multi-country cohort. BJOG. 2014;121(7):850–857.
• World Health Organization. WHO recommendations on antenatal care for a positive pregnancy experience. Geneva: WHO; 2016.
• Institute of Medicine. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington, DC: National Academies Press; 2009.
• ACOG Committee Opinion 804: Physical Activity and Exercise During Pregnancy and the Postpartum Period. 2020.

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Pregnancy Calculator

Calculate your due date and pregnancy week based on last menstrual period or conception date. Track trimester milestones. Free pregnancy due date calculator.

Reviewed by CalculatorApp.me Health Team

Pregnancy Calculator — Complete Guide

Due date calculation methods, pregnancy weeks by trimester, Naegele's rule, fetal development milestones, and prenatal care timeline.

40 weeks

Average pregnancy duration

280 days

From LMP to due date

3

Trimesters of pregnancy

±2 weeks

Normal delivery window

How Is a Due Date Calculated?

A pregnancy due date (estimated date of delivery, EDD) marks 40 weeks — 280 days — from the first day of the last menstrual period (LMP). This convention is used because ovulation and conception typically occur around day 14 of a 28-day cycle, making LMP a consistent and verifiable starting point even when the exact conception date is unknown.

The standard formula is Naegele's Rule: subtract 3 months from the LMP date, add 7 days, and add 1 year. Only approximately 4% of babies are born on their exact due date — the normal range is 37–42 weeks (term pregnancy). Babies born before 37 weeks are preterm; after 42 weeks is post-term.

Ultrasound dating, particularly the first-trimester crown-rump length (CRL) measurement at 7–13 weeks, is considered more accurate than LMP-based dates — especially for women with irregular cycles. If ultrasound and LMP dates differ by more than 7 days (first trimester), the ultrasound date is typically used to set the EDD.

Due Date Calculation Methods

Naegele's Rule (LMP Method)

EDD = LMP + 280 days
or equivalently:
EDD = LMP − 3 months + 7 days + 1 year

Example (LMP = 1 March 2025):
  Step 1: 1 March − 3 months = 1 December 2024
  Step 2: 1 December + 7 days = 8 December 2024
  Step 3: 8 December 2024 + 1 year = 8 December 2025
  EDD = 8 December 2025

Adjust for cycle length:
  Standard assumes 28-day cycle.
  If cycle = 35 days:
    Add (35 − 28) = 7 extra days
  If cycle = 21 days:
    Subtract (28 − 21) = 7 days

Accuracy: ±2 weeks for most women

Naegele's rule was proposed by Franz Karl Naegele in 1812 and remains the standard clinical calculation. It assumes a 28-day cycle with ovulation on day 14. It can be adjusted for cycle length variations.

Conception Date Method

If conception date is known:
  EDD = Conception date + 266 days
  (38 weeks from conception)

Note: 280 days from LMP = 266 days
from ovulation/conception (2 weeks later)

Example:
  Conception: 14 March 2025
  EDD = 14 March + 266 days
  EDD = 5 December 2025

When conception is known:
  • IVF transfers (exact date known)
  • Confirmed ovulation with testing
  • Single unprotected encounter

IVF transfer calculation:
  Day 3 transfer: add 263 days
  Day 5 transfer: add 261 days

For IVF pregnancies, the transfer date is precisely known. Adjustments are made based on embryo age at transfer: a day-5 blastocyst transfer subtracts 5 days from the 266-day conception formula.

Pregnancy Trimesters — Week by Week

First Trimester

Weeks 1–12

•Week 4: Positive pregnancy test possible
•Week 5–6: Heartbeat detectable by transvaginal US
•Week 8: Embryo becomes a fetus
•Week 10: Basic organ systems formed
•Week 12: Risk of miscarriage drops significantly

Most critical period for organ formation. Folic acid 400–800 mcg/day essential to prevent neural tube defects.

Second Trimester

Weeks 13–26

•Week 13–16: Gender may be visible on ultrasound
•Week 18–22: Anatomy scan (detailed ultrasound)
•Week 20: Fundal height = 20 cm (navel level)
•Week 24: Viability threshold (with intensive NICU care)
•Week 25–26: Lungs begin producing surfactant

Often called the 'honeymoon trimester' — morning sickness usually resolves and energy returns. Fetal movements typically felt (quickening) at 18–22 weeks.

Third Trimester

Weeks 27–40

•Week 28: Fetus is 36 cm, weighs ~1 kg
•Week 32: Most body systems functional
•Week 36: Considered 'late preterm'
•Week 37: Full term begins
•Week 40: Expected due date
•Week 41–42: Post-dates monitoring begins

Baby gains most of its weight during this trimester. GBS screening at 36 weeks. Prenatal visits increase to weekly after 36 weeks.

Prenatal Visit Schedule

Weeks	Visit Frequency	Key Tests/Milestones
4–8	First visit	Confirm pregnancy, blood type, CBC, STI screening, genetic carrier screening
10–13	Every 4 weeks	NIPT/cell-free DNA testing (optional), first trimester screening
18–22	Once	Anatomy ultrasound — checks all fetal organs
24–28	Every 4 weeks	Glucose tolerance test (gestational diabetes), Rh factor check
28–36	Every 2 weeks	Blood pressure, fundal height, fetal position
36+	Weekly	GBS culture (36 wk), fetal monitoring if post-dates

Frequently Asked Questions

How accurate is a due date calculator?▼

Due date calculators based on LMP are accurate to within ±2 weeks for most women with regular cycles. The actual variation in gestational length is significant — only about 4% of babies are born on their exact due date. First-trimester ultrasound dating is more accurate and is used to confirm or revise the EDD.

What does gestational age vs. fetal age mean?▼

Gestational age is counted from the LMP (the clinical standard) and is typically 2 weeks longer than fetal age (counted from conception). When a doctor says 'you are 8 weeks pregnant,' they mean 8 weeks from LMP — your baby is actually about 6 weeks post-conception. All due date calculators use gestational age.

When should I take a pregnancy test?▼

Home urine pregnancy tests detect hCG from about 10–14 days after conception — typically around the time of a missed period. Testing too early may give false negatives. For most reliable results, test the first morning urine on the day of your expected period or after.

References & Clinical Sources

ACOG Practice Bulletin. Methods for Estimating the Due Date. Obstetrics & Gynecology. 2017;129(5):e150–e154.
Naegele FC. Lehrbuch der Geburtshülfe. Heidelberg: Mohr und Zimmer, 1812.
WHO. WHO recommendations on antenatal care for a positive pregnancy experience. 2016.
Mongelli M, et al. Influence of conception date on the accuracy of gestational age estimation. Ultrasound Obstet Gynecol. 1996;8(5):318–22.

Due Date Calculator Ovulation Calculator Period Calculator

Methodology, sources & limitations

This calculator uses a published formula and the values entered in the calculator to generate the result.

Formula: EDD = LMP + 280 days
Jurisdiction & units: Intended for US, IN, EU, GB, Global. Supports both units where applicable.
Assumptions & limitations: Results are screening or educational estimates based on the inputs you provide. They do not diagnose, treat, or replace advice from a qualified clinician.
Review status: Formula and automated QA completed June 21, 2026; independent professional review is pending. Next scheduled review: September 21, 2026.

Validation sources

ACOG Practice Bulletin
WHO Pregnancy Guidelines

Pregnancy Due Date Calculator — Answer & Method

Calculate estimated due date and pregnancy milestones using Naegele's rule.

Formula: Naegele's Rule

EDD = LMP + 280 days

LMP = Last Menstrual Period (date)

Example Calculation

With LMP of January 1, 2026, the estimated due date is October 8, 2026.

Important limitation

This is an educational estimate, not a diagnosis or a substitute for professional medical advice.

Key Facts

Naegele's rule estimates delivery at 280 days (40 weeks) from the first day of the last menstrual period.
Only about 5% of babies are born on their exact due date.

Sources & Validation

ACOG Practice BulletinWHO Pregnancy Guidelines

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Deterministic: YesAI-Generated Numbers: NoVerified: 2026-02-12

Pregnancy Calculator

📅 Calculate Due Date

Enter your details

Understanding Pregnancy & Due Date Calculation

🗓️ How Due Date Calculation Works

Naegele's Rule

LMP vs. Conception Date

🩸 LMP Method

🥚 Conception Date

📅 Pregnancy Timeline by Week

🏥 Prenatal Care Schedule

⚖️ Pregnancy Weight Gain Guidelines

📜 History of Pregnancy Dating

🎯 How Accurate Is Your Due Date?

LMP Method

1st-Trimester Ultrasound

2nd/3rd Trimester Ultrasound

Why Babies Don't Arrive on the Due Date

🔬 Research & Clinical Guidelines

Methods for Estimating the Due Date

Distribution of Gestational Length at Birth

WHO Antenatal Care Recommendations

💡 Pregnancy Myths vs. Facts

❓ Frequently Asked Questions

📋 References & Further Reading

Related Calculators

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Explore All Health Calculators

Pregnancy Calculator

Pregnancy Calculator — Complete Guide

How Is a Due Date Calculated?

Due Date Calculation Methods

Pregnancy Trimesters — Week by Week

First Trimester

Second Trimester

Third Trimester

Prenatal Visit Schedule

Frequently Asked Questions

References & Clinical Sources

Methodology, sources & limitations

Validation sources

Pregnancy Due Date Calculator — Answer & Method

Formula: Naegele's Rule

Example Calculation

Important limitation

Key Facts

Sources & Validation

Related Calculators

Related Articles

Pregnancy Due Date Calculator Guide

See Also

Due Date Calculator

Ovulation Calculator

Period Calculator

Pregnancy Calculator

📅 Calculate Due Date

Enter your details

Understanding Pregnancy & Due Date Calculation

🗓️ How Due Date Calculation Works

Naegele's Rule

LMP vs. Conception Date

🩸 LMP Method

🥚 Conception Date

📅 Pregnancy Timeline by Week

🏥 Prenatal Care Schedule

⚖️ Pregnancy Weight Gain Guidelines

📜 History of Pregnancy Dating

🎯 How Accurate Is Your Due Date?

LMP Method

1st-Trimester Ultrasound

2nd/3rd Trimester Ultrasound

Why Babies Don't Arrive on the Due Date

🔬 Research & Clinical Guidelines

Methods for Estimating the Due Date

Distribution of Gestational Length at Birth