A Single pregnancy can feel reassuring—one heartbeat, one due date. And still, questions pop up fast: scans, supplements, blood pressure, baby’s movements, travel, work, delivery choices. A Single pregnancy is usually simpler than twins, but it isn’t “no monitoring”. It’s steady, structured, and meant to keep both mother and baby safe.

Single pregnancy: what to expect week by week

What “Single pregnancy” means and common terms

A Single pregnancy (a singleton gestation) means one fetus is developing in the uterus. Gestational age is counted from the first day of the last menstrual period (LMP).

Trimester language:

• First trimester: weeks 1–12
• Second trimester: weeks 13–26
• Third trimester: weeks 27–40

“Term” matters:

• Early term: 37+0 to 38+6
• Full term: 39+0 to 40+6
• Late term: 41+0 to 41+6
• Post-term: 42+0 and beyond

Single vs multiple pregnancy: what changes

Twins/triplets usually mean more nausea, more scans, more visits, and earlier delivery planning.

In a Single pregnancy, follow-up is often lighter—yet blood pressure, growth, placenta position, amniotic fluid, and fetal well-being still need routine checks.

Key milestones to remember

• Weeks 5–6: scan may confirm pregnancy location, heartbeat may be seen around 6 weeks with a transvaginal scan.
• Weeks 11–14: NT scan may be offered.
• Weeks 18–22: anatomy scan.
• Weeks 24–28: gestational diabetes screening.
• Weeks 37–40: term window.

Confirming a Single pregnancy and dating the due date

Home pregnancy tests and early confirmation

Urine tests detect hCG. A negative test can happen if it’s too early or urine is diluted.

Early clinic visits may include urine/blood testing and review of LMP. In specific situations (bleeding, pain, unclear dates), serial hCG and repeat ultrasound may be used.

Dating ultrasound (CRL)

Ultrasound confirms how many embryos are present and dates the pregnancy. CRL (crown–rump length) from about 7–13 weeks is the most accurate dating method.

A due-date shift of a few days compared with LMP is common, especially with irregular cycles.

Viability and ectopic pregnancy safety checks

A fetal heartbeat is often detectable around 6 weeks by transvaginal scan, sometimes later.

Early pregnancy also checks location: intrauterine vs ectopic. Seek urgent care for heavy bleeding, severe one-sided pain, shoulder-tip pain, dizziness, or fainting.

Your pregnancy basics: placenta, fluid and umbilical cord

Placenta location (why it’s checked)

Placenta location may be anterior, posterior, fundal, or lateral. A low-lying placenta at the mid-pregnancy scan often moves upwards as the uterus grows.

Two findings can change follow-up:

• Placenta previa (near/covering cervix): bleeding risk, may need planned caesarean.
• Placenta accreta spectrum (abnormal attachment): more likely after prior uterine surgery, affects delivery planning.

Amniotic fluid: low vs high

Amniotic fluid is measured by ultrasound:

• AFI: about 5–25 cm often considered normal.
• SDP: roughly 2–8 cm commonly used.

Low fluid (oligohydramnios) may be linked with ruptured membranes, post-term pregnancy, or placental underperformance.

High fluid (polyhydramnios) can be associated with diabetes or fetal conditions and may raise preterm labour risk.

Umbilical cord insertions

Marginal and velamentous cord insertions may need extra attention on scans. If vessels cross the cervix (vasa previa), delivery planning becomes highly specific.

Prenatal care schedule in a Single pregnancy

First prenatal visit: what usually happens

• medical and pregnancy history, medication review
• blood pressure, weight, BMI
• labs: CBC, blood group/Rh and antibody screen, infection screening, urine testing
• discussion of screening options (NT/combined screening, NIPT)

Visit frequency

Common low-risk schedule:

• up to 28 weeks: every 4 weeks
• 28–36 weeks: every 2 weeks
• from 36 weeks: weekly

Extra visits may be needed for hypertension, diabetes, placenta issues, bleeding, reduced movements, or growth concerns.

Routine checks

Most visits include blood pressure, weight trend, often urine dipstick, and fetal heart rate checks.

Fundal height is usually measured from around 18–20 weeks. If it’s off track, ultrasound may be advised.

Screening and testing by trimester

First trimester

• NT scan (11–14 weeks)
• combined screening (where offered)
• NIPT from about 9–10 weeks

Second trimester

• anatomy scan (18–22 weeks)
• serum screening (quad/AFP) where offered

Third trimester

• gestational diabetes screen (24–28 weeks)
• GBS swab (35–37 weeks) in many settings
• repeat CBC for anaemia

Diagnostic tests (when screening is higher risk)

• CVS (10–13 weeks)
• amniocentesis (15–20 weeks)

Ultrasounds during a Single pregnancy

Routine scans often include dating and anatomy scans. Growth scans are added when needed—fundal height concern, hypertension/diabetes, prior growth issues, suspected macrosomia, or suspected fetal growth restriction. Doppler may be added if placental blood flow is questioned.

Nutrition, supplements and weight gain (Indian household reality)

Practical nutrition foundations

Aim for variety and consistency:

• Protein: dal, chana/rajma, paneer/curd, eggs, fish/chicken, soy
• Iron-rich foods plus vitamin C (nimbu, amla, guava) for better absorption
• Fibre and fluids to reduce constipation

If nausea is strong, smaller frequent meals may be easier.

Supplements

Prenatal regimens often include folic acid, iron, calcium, iodine, and vitamin D. Avoid taking iron and calcium together, spacing them improves absorption.

Weight gain ranges

Typical singleton guidance:

• BMI <18.5: 12.5–18 kg
• BMI 18.5–24.9: 11.5–16 kg
• BMI 25–29.9: 7–11.5 kg
• BMI ≥30: 5–9 kg

Lifestyle: exercise, work, travel and sleep

For most uncomplicated Single pregnancy journeys, moderate activity is beneficial (often a goal of 150 minutes per week). Walking and prenatal yoga are popular choices.

For long travel: move legs, hydrate, and use the seat belt correctly (lap belt under the belly).

Left-side sleeping and supportive pillows can reduce back and hip strain.

Avoid alcohol, avoid smoking/vaping and drugs, keep caffeine moderate.

Who may need closer monitoring

A Single pregnancy may need tighter follow-up with age 35+, underweight/obesity, hypertension, diabetes, kidney/thyroid disease, prior preterm birth, prior caesarean, or IVF.

Common complications to know

• Bleeding: heavy bleeding or severe pain needs urgent care.
• Hyperemesis gravidarum: severe vomiting with dehydration may need medicines/IV fluids.
• Anaemia: common, ask about haemoglobin and iron levels.
• Hypertensive disorders (including preeclampsia): watch for severe headache, vision changes, right upper abdominal pain, sudden swelling.
• Preterm labour or leaking fluid: needs prompt assessment.

Monitoring baby’s well-being

From around 28 weeks, reduced movement compared with your baby’s usual pattern is a reason to call.

NST and BPP assess well-being when risk is higher. Doppler studies may be added in fetal growth restriction to evaluate placental resistance and fetal adaptation.

Birth planning and delivery options

Most uncomplicated Single pregnancy births happen between 39–41 weeks. Induction may be offered for post-term pregnancy, ruptured membranes, or maternal conditions.

Pain relief options may include epidural, medications, and non-medication comfort measures.

Caesarean may be needed for labour arrest, fetal heart rate concerns, breech, placenta previa, or other obstetric reasons.

Key takeaways

• A Single pregnancy means one baby, care is often simpler than twins, but regular monitoring still matters.
• First-trimester CRL dating gives the most accurate due date.
• Screening is trimester-based (NT/NIPT early, anatomy scan mid-pregnancy, diabetes/GBS later), with CVS/amniocentesis when needed.
• Learn red flags: heavy bleeding, leaking fluid, preeclampsia symptoms, fever, persistent vomiting, or reduced movements.
• Support exists. You can also download the Heloa app for personalised guidance and free child health questionnaires.