Summary:
- Antenatal care follows a trimester schedule: chromosomal screening at 11 to 13 weeks, anatomy scan at 18 to 22 weeks, gestational diabetes testing at 24 to 28 weeks, and growth scans through the third trimester.
- Non-invasive prenatal testing (NIPT) offers higher accuracy than standard screening but is not a diagnostic test. A positive result requires follow-up with chorionic villus sampling (CVS) or amniocentesis.
- Higher-risk pregnancies (maternal age over 35, multiples, pre-existing conditions, or complications such as pre-eclampsia or placenta praevia) require more frequent monitoring and specialist involvement.
Pregnancy brings a lot of firsts: your first ultrasound scan, your first time hearing your baby’s heartbeat, your first conversation with an obstetrician. For most women, it also brings uncertainty about what to expect and when.
This guide walks you through the checks, scans, and appointments that make up standard antenatal care, trimester by trimester, so you feel prepared before you walk into an obstetrics and gynaecology clinic.
What Happens During The First Trimester?
The first trimester is often when you will have the most questions and the least certainty. Here is what your care will typically involve during these early weeks.
Confirming Pregnancy
Your first step is to confirm the pregnancy with an obstetrician (a doctor who specialises in pregnancy and childbirth).
Obstetric care typically begins with a comprehensive review of your medical history, discussion of any pre-existing conditions, and a personalised plan for your pregnancy from the outset.
Early Ultrasounds And Fetal Development
An early ultrasound is commonly performed between 6 and 10 weeks’ gestation, depending on when the pregnancy is first assessed.
This confirms that the pregnancy is located inside the uterus rather than elsewhere, checks for a fetal heartbeat, and establishes your gestational age. In some cases, more than one early scan may be recommended.
Blood Tests And Prenatal Screening
Your first trimester involves two distinct rounds of testing. The blood panel covers the basics; the combined screen looks specifically at chromosomal risk.
First trimester blood panel:
- Blood type and rhesus (Rh) factor
- Full blood count
- Rubella immunity
- Hepatitis B and C
- HIV
- Thyroid function
Combined first-trimester screening (11 to 13 weeks):
- Assesses the risk of chromosomal conditions such as Down syndrome (trisomy 21)
- Combines an ultrasound measurement with blood markers
What Checks Are Done During The Second Trimester?
Detailed Fetal Anatomy Scan
It examines your baby’s brain, heart, spine, limbs, kidneys, and facial features in detail. It also assesses the position of the placenta (the organ that delivers nutrients and oxygen to your baby) and the volume of amniotic fluid (the fluid surrounding the baby in the womb).
Monitoring Baby's Growth And Development
Screening Tests Recommended During Mid-Pregnancy
Between 24 and 28 weeks, a glucose challenge test or oral glucose tolerance test (OGTT) is used to screen for gestational diabetes (raised blood sugar levels that develop during pregnancy).
If you are Rh negative, a blood test will check for Rh antibodies, and an anti-D injection may be recommended to reduce the risk of Rh sensitisation during the current and future pregnancies.
Confirmed your pregnancy but not sure what comes next? At Pacific Healthcare Specialist Centre (Women’s Clinic), our obstetricians can discuss your pregnancy, explain the recommended schedule of antenatal care and answer any questions you may have. Book an appointment today.
How Does Care Change In The Third Trimester?
Tracking Fetal Growth And Wellbeing
A biophysical profile (a scan that assesses foetal movement, breathing, and muscle tone alongside amniotic fluid levels) may be used to check your baby’s overall wellbeing.
Preparing For Labour And Delivery
From around 36 weeks, your obstetrician will discuss your birth plan, the likely mode of delivery, and what to expect during labour. They will offer guidance on all delivery options, including natural birth, medicated birth, and caesarean section.
A vaginal swab for Group B Streptococcus (GBS), a type of bacteria that can affect newborns during delivery, may be recommended between 35 and 37 weeks, depending on your doctor’s practice and individual risk factors.
Final Health Checks Before Birth
During your final appointments your doctor will confirm your baby’s position, assess the cervix (the lower part of the uterus that opens during labour), and review any outstanding test results.
If your pregnancy continues past 41 weeks, your obstetrician will discuss the option of induction (medically stimulating labour).
Which Prenatal Screening And Blood Tests Will You Need?
| Test | What it assesses | When |
|---|---|---|
| Blood panel | Blood group and Rh factor, haemoglobin levels (anaemia), infectious disease screening (hepatitis B and C, HIV, rubella), thyroid function, and vitamin D and folate where indicated | Throughout pregnancy, starting at the first visit |
| Combined first-trimester screen | Risk of chromosomal conditions such as Down syndrome (trisomy 21), using an ultrasound measurement and blood markers | 11 to 13 weeks |
| Non-invasive prenatal testing (NIPT) | Fragments of fetal DNA in your bloodstream, to assess the likelihood of chromosomal conditions; not a diagnostic test, but offers higher accuracy than standard screening alone | Usually offered after the combined screen, or from 10 weeks |
| Oral glucose tolerance test (OGTT) | Gestational diabetes (raised blood sugar levels during pregnancy) | 24 to 28 weeks |
| Further diagnostic tests (CVS or amniocentesis) | Chromosomal abnormalities; recommended only if screening indicates an increased likelihood of a chromosomal condition | As directed by your obstetrician |
When Will You Need Pregnancy Ultrasounds?
| Scan | Purpose | Timing |
| Dating scan | Confirms gestational age and establishes your due date; forms the baseline for all subsequent assessments | First trimester (usually 6 to 10 weeks) |
| Anatomy scan | Assesses fetal structure in detail, checking major organ development and identifying any abnormalities requiring further investigation | 18 to 22 weeks |
| Growth and well-being scans | Monitors fetal size, placental health, and amniotic fluid levels; frequency varies by individual pregnancy | Third trimester, as advised by your obstetrician |
Every pregnancy follows its own timeline. Speak to Dr Nurhidayati at Pacific Healthcare Specialist Centre (Women’s Clinic) to discuss which scans and investigations may be appropriate for your pregnancy.
When Is Additional Pregnancy Monitoring Recommended?
What Defines A High-Risk Pregnancy?
A pregnancy may be considered higher risk if you are over 35, carrying multiple babies, have a pre-existing condition such as diabetes, hypertension, or a clotting disorder, or if concerns arise during routine monitoring.
Pregnant adolescents may require additional monitoring because of increased maternal and fetal risks.
Common Conditions Requiring Closer Follow-Up
| Risk factor or Condition | Why It Requires Closer Monitoring |
| Maternal age over 35 or under 18 | Associated with higher rates of complications, including chromosomal abnormalities and gestational hypertension |
| Multiple pregnancy (twins or more) | Increases the risk of preterm labour, growth restriction, and other complications |
| Pre-existing diabetes, hypertension, or clotting disorder | May worsen during pregnancy and affect fetal development |
| Gestational diabetes | Requires dietary management and closer fetal growth monitoring to reduce risks at delivery |
| Pre-eclampsia | High blood pressure with organ involvement; can escalate quickly and require early delivery |
| Intrauterine growth restriction | Indicates the baby is not growing as expected; requires serial scans to assess placental function |
| Placenta praevia | Placenta lying directly over the cervical opening; may cause bleeding and affect delivery planning |
How Do Obstetricians Monitor Higher-Risk Pregnancies?
Book An Obstetric Consultation To Plan Your Care
No two pregnancies are the same, and your care should reflect that. Having an obstetrician who knows your history and can respond to changes as they arise makes a meaningful difference to how your pregnancy is managed.
Dr Nurhidayati Binte Mohamed Suphan, Consultant Obstetrician and Gynaecologist at Pacific Healthcare Specialist Centre (Women’s Clinic) in Singapore, offers personalised obstetric care from confirmation through to delivery, with experience in caring for women with both routine and higher-risk pregnancies.
