Key takeaways

  • Doctors measure pregnancy in weeks from the first day of your last period (LMP), so you are counted as "pregnant" about two weeks before conception actually happens.
  • A full-term pregnancy is 40 weeks (280 days) from LMP. This works out to a little over 9 calendar months, which is why month 9 stretches from week 36 to week 40.
  • Pregnancy is divided into three trimesters: first (weeks 1-13), second (weeks 14-27), and third (weeks 28-40).
  • Your due date (EDD) is an estimate, not a deadline. Only about 4-5% of babies arrive on the exact date; most come within two weeks either side.
  • A first-trimester ultrasound is more accurate than your period date for setting the due date, especially with irregular cycles.
  • Each month has its own scans, blood tests, and vaccines in the Indian antenatal schedule, plus traditional celebrations like Godh-bharai, Seemantham and Valaikappu.

How Pregnancy Weeks Convert to Months

The first thing to understand is where the counting starts. Doctors measure gestational age (GA) from the first day of your last menstrual period (LMP) — even though conception usually happens about two weeks later, around ovulation. This sounds odd, but it is used worldwide for a simple reason: most women know when their last period started, while almost nobody knows the exact day they conceived.

So when your doctor says you are "8 weeks pregnant," they mean 8 weeks since your LMP — roughly 6 weeks since conception. If your cycles are irregular or you are unsure of your LMP, an early scan sets the dates instead (more on that below).

A full-term pregnancy lasts 40 weeks (280 days) from LMP, or about 38 weeks (266 days) from conception. The normal term range is 37 to 42 weeks. Babies born before 37 weeks are preterm; those born after 42 weeks are post-term.

The weeks-to-months conversion that matches the way Indian families usually count (the familiar "9 months") is:

  • Month 1: weeks 1–4
  • Month 2: weeks 5–8
  • Month 3: weeks 9–13
  • Month 4: weeks 14–17
  • Month 5: weeks 18–22
  • Month 6: weeks 23–27
  • Month 7: weeks 28–31
  • Month 8: weeks 32–35
  • Month 9: weeks 36–40

Notice that month 9 covers five weeks (36 to 40), not four. That is because 40 weeks simply does not divide evenly into nine four-week months — there are a few extra days left over, which is also why pregnancy feels like "9 months and a bit."

Some traditions instead use 10 lunar months of 28 days each, which divides 40 weeks evenly (10 × 4 weeks). Indian reckoning sometimes counts these 10 lunar months from the missed period, which is where the "10 months" you may hear from elders comes from. Both ways of counting describe the same pregnancy — just with different-length "months."

At a visit, your Ob-Gyn will often say something like "14 weeks 3 days," meaning 14 complete weeks plus 3 extra days — mid-month 4. The trimester structure (below) ties all of this together.

The Three Trimesters at a Glance

Pregnancy is split into three blocks called trimesters. Each has its own milestones, symptoms, and tests.

  • First trimester — weeks 1 to 13 (months 1 to 3). All the major organs form in this window (organogenesis), and it carries the highest risk of Miscarriage: Types, Recovery and Care in India. Symptoms like nausea and fatigue often peak here.
  • Second trimester — weeks 14 to 27 (months 4 to 6). Often the most comfortable phase: nausea usually eases and energy returns. Quickening (the first movements you feel) typically arrives at 18–22 weeks in a first pregnancy and 16–20 weeks in later ones. The detailed anomaly scan is done at 18–20 weeks.
  • Third trimester — weeks 28 to 40. The focus shifts to your baby's growth, lung maturation, and getting ready for birth.

The rest of this guide walks through what each month brings.

Month 1 (Weeks 1 to 4): Implantation and Earliest Pregnancy

Month 1 covers weeks 1 to 4 from LMP — roughly the first calendar month after a missed period. Because counting starts at your LMP, weeks 1 and 2 happen before conception. Conception occurs around ovulation (about cycle day 14 in a 28-day cycle); week 3 is the week of conception and earliest cell division; and during week 4 the early embryo implants into the lining of the uterus and connects to your blood supply.

At week 4 the embryo is about 0.4 mm — smaller than a sesame seed. The blastocyst (early ball of cells) implants around day 21–26 after LMP, the placenta and amniotic sac begin to form, and a yolk sac provides early nutrition until the placenta takes over by week 12.

What you may feel. Symptoms in month 1 are usually mild, and many women do not yet realise they are pregnant. The expected period is missed around week 4. Early signs can include breast tenderness, mild fatigue, more frequent urination, light cramping (different from period cramps), implantation spotting (light pink or brown discharge for a day or two around days 21–26), and a heightened sense of smell.

Confirming the pregnancy. The hormone hCG becomes detectable about 6–8 days after conception. Sensitive home urine tests (i-can, Prega News, Velocit, Mankind Pregakem, roughly ₹60–₹200) can pick up pregnancy from about a day after a missed period; a blood (serum beta-hCG) test detects it even earlier and is used in clinics. If you see a faint line on a home test, it usually still counts as positive — repeat in a couple of days or confirm with a blood test.

Folic acid — start it early. ICMR and FOGSI advise folic acid 400–800 mcg daily, ideally begun about 3 months before conception, because the baby's neural tube closes during weeks 3–6 — before many women know they are pregnant. If you have not started, begin now. Read more on folic acid before conception. Common brands include Folvite, Nuforce and Foracal (₹50–₹300).

Lifestyle precautions: avoid alcohol completely, limit caffeine to under 200 mg a day, stop tobacco and recreational drugs, review every prescription and over-the-counter medicine with a doctor, avoid known teratogens (unshielded X-rays, certain workplace chemicals, raw or undercooked meat and fish), and continue your prenatal vitamin.

First visit. Once a test is positive, book your first Ob-Gyn appointment — the first month and your first antenatal booking explains what to expect. The typical first visit at 6–8 weeks includes confirming the pregnancy, baseline bloods (haemoglobin, blood group and Rh, HIV, hepatitis B and C, syphilis, rubella, thyroid, fasting glucose), urine testing, blood pressure and weight, and an early dating scan if your LMP is uncertain. A first consultation costs roughly ₹500–₹3,000 at private FOGSI-affiliated clinics, and is free or subsidised at government hospitals.

Months 2 to 3 (Weeks 5 to 13): First Trimester

Months 2 and 3 cover weeks 5 to 13 and complete the first trimester. This is the period of fastest development — all major organs form between weeks 4 and 10 (organogenesis).

Your baby's development. By week 8 the embryo is about 1.6 cm (a kidney bean), with all major organs present in early form. The heart starts beating around weeks 5–6 and can be seen on a transvaginal scan by weeks 6–7. From week 9 the embryo is called a foetus. By week 12 it is about 5–6 cm (a lime), weighs around 14 g, has formed fingers and toes, closed eyelids, and kidneys making urine; the placenta is now fully working.

What you may feel. First-trimester symptoms peak for many women. Morning sickness (nausea, with or without vomiting) affects roughly 70–85% of pregnant women, usually peaking around week 9 and easing by weeks 14–16. A severe form, hyperemesis gravidarum, affects about 0.5–2% and may need hospital care. Profound fatigue, tender breasts, frequent urination, constipation, bloating, food aversions and mood swings are all common. For a fuller week-by-week picture, see first-trimester symptoms for Indian women.

Tests and milestones. This stage includes your first scan (weeks 7–9), early blood work, and screening for chromosomal conditions: the first-trimester combined screening (NT scan plus dual marker) at 11 to 13+6 weeks, and the option of NIPT from week 10.

Managing nausea safely. Focus on hydration and small frequent meals. ACOG supports vitamin B6 (pyridoxine) 10–25 mg three to four times daily, with a doxylamine-plus-pyridoxine combination (e.g. Doxinate) added for moderate-to-severe nausea. Avoid hot baths and saunas above about 39°C in this period. Keep taking folic acid; iron is usually started around weeks 12–14 once nausea improves.

Miscarriage risk. Most miscarriages happen before week 12 and are due to chromosomal abnormalities — not anything the mother did or did not do. The risk falls significantly once a heartbeat is documented around weeks 6–7 and keeps dropping through week 13. This is why many Indian families wait until the end of the first trimester before announcing the pregnancy.

Months 4 to 6 (Weeks 14 to 27): Second Trimester

Months 4 to 6 cover weeks 14 to 27 — often called the "honeymoon trimester" because nausea usually settles, energy returns, and the bump appears without yet being uncomfortable. Our full second-trimester week-by-week guide goes deeper, and 6 months pregnant covers this trimester's most important weeks.

Your baby's development. By week 16 the foetus is about 12 cm and 100 g; the external genitalia have formed (though sex disclosure is illegal in India under the PC-PNDT Act). By week 20 it is about 25 cm and 300 g (a banana), coated in vernix and fine lanugo hair, with clear sleep-wake cycles; quickening — the first movements you feel — typically arrives between weeks 18 and 22. By week 24 it is about 30 cm and 600 g; the lungs begin making surfactant, and this marks the threshold of viability. By week 27 it is about 36 cm and 1 kg, with eyes that open and a rapidly developing brain.

What you may feel. The bump becomes visible (usually 16–20 weeks) and weight gain picks up (target about 0.4–0.5 kg per week — see pregnancy weight-gain guidelines). Pigmentation changes intensify: melasma (the pregnancy mask), linea nigra, and darker areolae. You may notice round ligament pain as the uterus stretches, mild ankle swelling, and nasal congestion.

Tests and milestones. This trimester brings monthly visits, the detailed TIFFA anomaly scan at 18–20 weeks, the OGTT for gestational diabetes at 24–28 weeks (DIPSI single-step 75 g test in India), and anti-D for Rh-negative mothers at 28 weeks.

Traditional celebrations. Godh-bharai, Seemantham and Valaikappu are usually held in months 5 to 8 depending on region and family (covered in the rituals section below).

Lifestyle. Aim for a balanced diet with enough calcium (1,000–1,200 mg/day from milk, paneer, ragi, sesame and greens), iron (27 mg/day in pregnancy per ICMR), and protein (~71 g/day). See Indian superfoods during pregnancy for practical food ideas. Keep moving with a safe trimester-by-trimester exercise plan — brisk walking, prenatal yoga, swimming — plus pelvic-floor (Kegel) exercises, and use only pregnancy-safe skincare.

Months 7 to 9 (Weeks 28 to 40): Third Trimester

Months 7 to 9 cover weeks 28 to 40 — the period of greatest growth, peak symptoms, and preparation for birth. Our month guides go week by week: 7 months pregnant, 8 months pregnant and 9 months pregnant.

Your baby's development. By week 28 the foetus is about 38 cm and 1.1 kg, beginning to lay down fat, with stronger, more obvious movements. By week 32 it is about 42 cm and 1.7 kg, with formed (but still soft) bones; the head usually settles into the head-down (vertex) position by weeks 32–36. By week 36 it is about 47 cm and 2.6 kg, with nearly mature lungs. By week 40 — term — it averages about 50 cm and 3.2–3.5 kg for Indian babies, and is ready for birth.

What you may feel. Symptoms intensify: back, hip and pelvic pain; shortness of breath as the uterus presses on the diaphragm; heartburn; frequent night urination; swelling of the feet and ankles; Braxton-Hicks (practice) contractions; returning fatigue; and disrupted sleep. Colostrum may leak from the breasts, and in a first pregnancy the baby often "drops" into the pelvis (lightening) in the last 2–4 weeks.

Tests and milestones. Visits become more frequent — every 2–3 weeks from week 28, then weekly from week 36. Expect growth scans at weeks 28 and 34–36, anti-D at 28 weeks if Rh-negative, the Tdap vaccine between weeks 27 and 36 to protect your newborn from whooping cough, and group B streptococcus discussion around weeks 36–37. Now is the time for birth planning — see what a birth plan is.

Term definitions. Term begins at week 37: 37 to 38+6 weeks is early term, 39 to 40+6 is full term, 41 weeks is late term, and 42+ weeks is post-term. ACOG and FOGSI favour delivery at 39–40 weeks for routine pregnancies, with induction considered at 41 weeks and strongly indicated by 42 weeks.

Lifestyle. Prioritise rest and pelvic-floor exercises, consider perineal massage from week 34, attend birth-preparation classes, and get your hospital bag ready (see nesting for a checklist).

How Due Dates Are Calculated

Your estimated due date (EDD) — also called the estimated date of delivery or expected date of confinement — is worked out in one of two main ways.

Naegele's rule (from your LMP). The classic formula is LMP + 280 days, or equivalently LMP − 3 months + 7 days + 1 year. For example, an LMP of 1 April 2026 gives an EDD around 6 January 2027. Most clinics use a pregnancy wheel or app to do the precise day-by-day calculation. Naegele's rule assumes a 28-day cycle with ovulation on day 14, so if your cycles are longer or shorter, the date shifts accordingly.

First-trimester ultrasound. A scan in the first trimester is more accurate than the LMP, especially with irregular cycles, an unclear LMP, or recent stopping of the pill. The crown-rump length (CRL) measured at 7–12 weeks predicts the EDD to within about 3–5 days. ACOG and FOGSI recommend using ultrasound dating to revise the EDD if it differs from the LMP-based date by more than 7 days. Dating becomes less accurate in the second and third trimesters because babies grow at different rates, so the EDD should ideally be locked in during the first trimester. (For help reading these reports, see our guide to understanding scans, labs and reports.)

How reliable is the date? Only about 4–5% of babies arrive on the exact due date. Around 60–70% arrive within a week of it, and about 90% within two weeks. Babies born before 37 weeks are preterm; those reaching 42 weeks are post-term, which is generally avoided by induction.

IVF pregnancies are dated from the embryo transfer date plus the embryo's age (e.g. day-5 embryo), which is highly accurate because conception is known precisely.

Many apps calculate weeks, months and EDD automatically — but always confirm the date with your Ob-Gyn at your first visit. And remember: the EDD is the centre of a range, not a deadline. Telling family and employers "early-to-mid January" rather than one fixed date takes a lot of pressure off as it approaches.

Indian Cultural Pregnancy Rituals by Month

India has rich pregnancy traditions that vary by region, religion and family. Knowing the usual timing helps with planning — and these customs can sit happily alongside evidence-based antenatal care.

Godh-bharai (lap-filling) is the broad North, Central and West Indian baby-shower equivalent (Hindi belt, Maharashtra, Gujarat, Rajasthan, Punjab), usually in month 7 or 8 (weeks 28–35). The mother-to-be wears new clothes — often a red, pink or orange saree or lehenga — and is showered with fruits, sweets, jewellery and blessings, with her lap symbolically filled with rice or fruit for fertility and abundance.

Seemantham (Seemantonayanam) is the South Indian (especially Tamil and Telugu) ceremony, typically in month 5 or 7 — a more ritualised Vedic ceremony performed by a priest, with the woman in a nine-yards saree, bangles and flowers.

Valaikappu is the Tamil bangle ceremony, usually in month 7. Glass bangles in odd numbers are stacked on the wrists; their sound is believed to soothe the baby. A yellow saree is traditional.

Regional variations include the Bengali Sadh (months 7–9, with kheer and payesh) and the Marathi Dohale jevan (months 5–7). The third trimester is also the traditional baby-shower window covered in our week 30 guide.

Maternal transfer to the parental home (mayke jana) for a first delivery is widespread: the woman moves to her parents' home around month 7–8 and stays through delivery and the first 40–60 days postpartum, for extra rest and support.

Common dietary customs include jaggery, ghee, dry fruits, milk and paneer, and the avoidance of certain foods (papaya in early pregnancy, excess sesame), although the scientific evidence for many food taboos is limited. Oil massage (Abhyanga) is popular in the second and third trimesters. Astrological observances may include caution during eclipses (sutak). If any custom worries you or conflicts with medical advice, talk it through with your Ob-Gyn.

Prenatal Visits and Tests Schedule

Antenatal care in India broadly follows FOGSI, ICMR, ACOG and NICE guidance.

First trimester (weeks 6–13): monthly visits, with the first at 6–8 weeks. The booking visit covers confirmation of pregnancy, a detailed history and examination, blood pressure and weight, baseline bloods (haemoglobin, blood group and Rh, HIV, hepatitis B and C, syphilis, rubella IgG, thyroid TSH, fasting glucose, vitamin D), urine analysis, an early dating scan, a folic-acid prescription and lifestyle counselling. NT scan plus combined screening or NIPT is offered at 11 to 13+6 weeks.

Second trimester (weeks 14–27): monthly visits, the anomaly (TIFFA) scan at 18–20 weeks, OGTT at 24–28 weeks, the Tdap vaccine between weeks 27 and 36, iron supplementation, and anti-D at 28 weeks for Rh-negative mothers.

Third trimester (weeks 28–40): visits every 2–3 weeks from week 28 and weekly from week 36, growth scans at 28 and 34–36 weeks, group B strep discussion at 36–37 weeks, foetal monitoring as indicated, and birth planning.

Government schemes make antenatal care free or low-cost: Janani Suraksha Yojana (JSY) gives cash assistance and free delivery in government hospitals; Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA) offers a free check-up on the 9th of every month; Pradhan Mantri Matru Vandana Yojana (PMMVY) gives ₹5,000 for a first live birth; and Janani Shishu Suraksha Karyakram (JSSK) covers free delivery and newborn care at public facilities.

Indicative private costs: routine consultation ₹500–₹2,000; ultrasound scans ₹800–₹5,000 each; blood-test panels ₹200–₹3,000; full pregnancy packages ₹25,000–₹1,50,000. Vaginal delivery in private hospitals runs roughly ₹50,000–₹3,00,000 and a C-section ₹1,00,000–₹5,00,000, with NICU charges extra. Most individual health insurance covers maternity only after a 2–4 year waiting period, so check your policy early. Government hospitals (AIIMS, KEM, JIPMER, PGI, state medical colleges) provide free or heavily subsidised care.

Keep an organised pregnancy folder with every report, scan and prescription, or use a digital record so nothing is lost between visits.

When to See a Doctor

  • Vaginal bleeding or fluid leaking from the vagina (possible miscarriage, placenta previa or labour)
  • Severe or persistent abdominal pain, or pain on one side with shoulder-tip pain in early pregnancy (possible ectopic pregnancy — an emergency)
  • A severe or persistent headache, blurred vision, flashing lights, or sudden swelling of the face and hands (possible preeclampsia)
  • A noticeable drop in your baby's movements after about 28 weeks
  • Fever above 38°C, painful or burning urination, or foul-smelling discharge
  • Regular tightening or cramping before 37 weeks (possible preterm labour)
  • Intense itching of the palms and soles, especially at night (possible cholestasis of pregnancy)
  • Persistent vomiting that stops you keeping fluids down (possible hyperemesis gravidarum)

Myths vs Facts

Frequently asked questions

How many weeks is 9 months pregnant?

Nine months pregnant covers roughly weeks 36 to 40. Because 40 weeks does not divide evenly into nine four-week months, month 9 stretches across five weeks rather than four.

Why do doctors count pregnancy from my last period and not from conception?

Because almost no one knows the exact day they conceived, but most women know when their last period started. Counting from the first day of your last menstrual period (LMP) gives a reliable, standard starting point worldwide — even though it counts you as 'pregnant' about two weeks before conception actually happens.

Is the due date the day my baby will be born?

No. The estimated due date (EDD) is the centre of a normal range, not a deadline. Only about 4–5% of babies are born on the exact date; most arrive within two weeks before or after. Anything from 37 to 42 weeks is considered term.

Which is more accurate for dating — my last period or an ultrasound?

A first-trimester ultrasound is more accurate, especially if your cycles are irregular, your LMP is uncertain, or you recently stopped the pill. ACOG and FOGSI advise revising the due date to match the scan if the two differ by more than 7 days. The scan is most accurate at 7–12 weeks.

When will I feel my baby move?

The first movements (quickening) are usually felt between 18 and 22 weeks in a first pregnancy and a little earlier (16–20 weeks) in later pregnancies. After about 28 weeks, a noticeable reduction in movement should always be checked the same day.

What is the difference between '9 months' and '10 lunar months'?

Both describe the same 40-week pregnancy. The familiar '9 months' counts ordinary calendar months and leaves a few extra days over. The '10 lunar months' system, sometimes used in Indian tradition, divides the 40 weeks into ten 28-day blocks, which fits evenly.

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