15 weeks pregnant means 15+0 to 15+6 weeks from the first day of your last period: about 3 months and 14 days, so you are in the 4th month. Your baby starts to hear this week, and if combined screening was not done, the window for the triple/quad test is coming up.
15 weeks pregnant (15+0 to 15+6 weeks) is about 3 months and 14 days from the first day of your last period. You are in the 4th month and in the second trimester.
The NHS says your baby is now around 10.1 cm from head to bottom, about the size of an apple. A soft layer of fine hair called lanugo is growing over the body, and eyebrows and eyelashes are developing. The eyes are sensitive to light. Around now your baby starts to hear: your voice, your heartbeat and the noises of your digestive system.
ACOG's summary for weeks 13 to 16 says the bones, especially the long bones, harden; the skin is thin and see-through but will soon start to thicken; toenails form; the neck is defined and the legs develop; and hearing starts to develop.
As your bump grows you may feel less steady on your feet; do not be shy about asking for a seat on public transport. You may get jabbing pains on the sides of the bump, known as round ligament pain; putting your feet up and resting can help (NHS).
Your skin may feel itchy: an unperfumed moisturiser, loose cotton clothing and a cool bath can help. The NHS advises telling your doctor or midwife if the itching gets worse, especially at night. With more blood flowing to the pelvic area, you may produce more of the milky discharge called leucorrhoea, which keeps the vagina clean.
If you have a vaginal infection, it is most likely thrush: lumpy white discharge, itching, and stinging when you pee or have sex. To help prevent it, wear loose cotton underwear, use unperfumed soap and avoid sex until it has cleared (NHS).
Chromosome screening: the Turkish Ministry of Health guideline (2026) offers the triple or quad test at 16 to 20 weeks if combined screening was not done; if it was, a triple/quad test for chromosome screening is not needed. ACOG offers the quad test at 15 to 22 weeks and gives its Down syndrome detection rate as 81% in its 2026 table. Screening tests do not diagnose: a positive result means a higher risk and a negative result a lower risk (ACOG, 2025).
Neural tube defect screening: the Turkish Ministry of Health says a blood alpha-fetoprotein (AFP) test can be done at 16 to 20 weeks. UpToDate says AFP is ideally measured at 16 to 18 weeks (possible from 15 to 22 weeks), but the generally preferred method is the detailed ultrasound at 18 to 22 weeks.
Under the Turkish Ministry of Health guideline, iron supplements start from 16 weeks for women without anaemia, and the next routine visit is between 18 and 24 weeks. NICE plans an appointment between 14 and 18 weeks to check blood pressure and test urine for protein.
| Symptom | Usually | Seek care if |
|---|---|---|
| More vaginal discharge | Clear, white or creamy discharge with a mild smell is normal (NHS). | If it changes colour, smells bad or fishy, turns frothy or looks like cottage cheese, or if you have pain when peeing, itching or soreness (NHS). |
| Itchy skin | Mild itching of the bump and skin is common; moisturiser and a cool bath can soothe it (NHS). | If the itching is getting worse, especially at night (NHS); unexplained itching is a danger sign in the Turkish Ministry of Health guideline. |
| Jabbing groin pain | Round ligament pain is common now and eases with rest (NHS). | If the pain is severe or constant, or comes with bleeding, cramps or leaking fluid. |
These are danger signs or emergency referral criteria in the Turkish Ministry of Health guideline; contact your doctor or go to the nearest emergency department without waiting. NICE recommends a hospital review for any unexplained bleeding after 13 weeks, and anti-D for women who are RhD negative and at risk of isoimmunisation. UpToDate notes that symptoms of cervical insufficiency (pelvic pressure, cramps, backache, more discharge or discharge turning pink or brown) usually begin between 14 and 20 weeks and can be mild.
Days 105 to 111 from the first day of your last period, or about 3 months and 14 days. You are in the 4th month.
The Turkish Ministry of Health guideline gives 16 to 20 weeks and ACOG 15 to 22 weeks. It is offered if combined screening was not done; according to the Turkish Ministry of Health, a repeat triple/quad test is not needed after a combined test.
Usually not reliably on ultrasound yet; UpToDate notes that ultrasound generally shows the sex at 17 to 20 weeks. A cell-free DNA test (NIPT) can report the sex along with chromosome screening, but a wrong result is possible.
According to the WHO fetal growth charts (2017), the median (50th percentile) estimated fetal weight at 15 weeks is 114 g, and the 10th to 90th percentile range is 99 to 132 g. These are reference values from ultrasound measurements in low-risk pregnancies in ten countries; the authors note differences between countries, with maternal factors and with fetal sex, and say the charts may need adjusting for local use. UpToDate adds that ultrasound weight estimates are generally not useful before about 24 weeks. The NHS gives a length of about 10.1 cm from head to bottom.
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