First Trimester Care Guide
Current Guidance Update
First Trimester Screening
First trimester combined screening remains the standard approach for chromosomal risk assessment at 11–14 weeks.
Low-Dose Aspirin
Women at high risk of preeclampsia should receive 150mg low-dose aspirin from 12 weeks of pregnancy.
Antenatal Contacts
A minimum of 8 antenatal contacts is recommended, with the first visit in the first trimester.
Cell-Free DNA (NIPT)
NIPT should be offered as a contingent screening test following combined first-trimester screening.
Introduction
The Booking Appointment
The booking appointment, ideally before 10 weeks, is the most comprehensive consultation in the antenatal pathway and includes the following assessments and investigations.
Detailed personal, family, and obstetric history.
Blood pressure measurement and urinalysis.
BMI calculation and nutritional assessment.
Blood group, antibody screen, and full blood count.
Rubella immunity, hepatitis B/C, HIV, and syphilis serology.
Haemoglobinopathy screening, particularly relevant in Dubai's diverse population.
Vitamin D level assessment and urine culture for asymptomatic bacteriuria.
Review of medications and lifestyle counseling.
Folic Acid and Supplementation
Combined First Trimester Screening (11–14 weeks)
Nuchal translucency ultrasound combined with maternal serum PAPP-A and free beta-hCG provides risk stratification for trisomy 21, 18, and 13, with Down syndrome detection rates of 85–90% at a 5% false-positive rate. The optimal window is 11 weeks 0 days to 13 weeks 6 days.
Cell-Free DNA / NIPT
NIPT using maternal blood cell-free DNA offers higher sensitivity (>99% for trisomy 21) with very low false-positive rates. RCOG and ACOG recommend NIPT as a contingent test following combined screening, or as a primary option for women preferring higher accuracy.
The Dating Scan
Performed between 11 and 14 weeks, this scan provides accurate gestational age dating via crown-rump length, assesses chorionicity in multiple pregnancies, allows early structural assessment, and supports NT measurement.
Common First Trimester Symptoms
Nausea and vomiting affect up to
80% of women, typically peaking between
8–12 weeks. Management includes dietary modification,
ginger, and antiemetics when required.
Hyperemesis gravidarum is a more severe
condition that requires medical treatment, including intravenous fluids
and thiamine supplementation.
The overall
miscarriage risk is approximately
10–15%, with the likelihood increasing as maternal age
advances.
Ectopic pregnancy occurs in around
1–2% of pregnancies and requires urgent clinical
assessment if unilateral abdominal pain or vaginal bleeding occurs
alongside a positive pregnancy test.
Lifestyle Guidance
Alcohol
no safe level identified; complete abstinence recommended
Smoking
cessation beneficial at any point in pregnancy
Caffeine
limit to under 200mg per day
Exercise
moderate-intensity exercise safe and beneficial in uncomplicated pregnancies
Food safety
avoid unpasteurised dairy, raw/undercooked meat and eggs, liver products, high-mercury fish
Preeclampsia Risk Assessment
The first trimester is the appropriate time to assess preeclampsia risk via combined screening (uterine artery Dopplers, mean arterial pressure, serum PlGF). High-risk women should receive aspirin 150mg daily from 11–14 weeks until 36 weeks, reducing preterm preeclampsia risk by approximately 62%.
Frequently Asked Questions
How many antenatal appointments are needed in the first trimester?
A minimum of one comprehensive booking appointment before 10 weeks and a dating/screening scan at 11–14 weeks. Women with risk factors require additional early appointments.
Is it safe to exercise in the first trimester?
Yes for most women. Moderate exercise is safe and beneficial; any new programme should be discussed with your obstetrician.
When does morning sickness usually stop?
For most women, nausea resolves by 12–16 weeks. Symptoms persisting beyond 16 weeks warrant clinical review.
What is NIPT and should I have it?
NIPT is a blood test screening for chromosomal conditions with high accuracy using fetal DNA from maternal blood. It is optional, not diagnostic, and particularly useful after a high-risk combined screen result.
Conclusion
The first trimester is a period of extraordinary biological change and significant clinical opportunity. Comprehensive booking assessment, timely supplementation, evidence-based screening, and clear lifestyle guidance establish the foundation for a safe, well-monitored pregnancy.
Sources & References
This article draws on guidance current at the time of writing from the following bodies and publications:
- ACOG (2024 Practice Bulletin #230)
- RCOG (2024)
- WHO (2024)
- NICE NG201 (updated 2023)
General reference bodies for women's health guidance:
RCOG
rcog.org.ukACOG
acog.orgFIGO
figo.orgWHO
who.intNICE
nice.org.uk⚠ IMPORTANT DISCLAIMER
This article is provided for general knowledge and reference purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. No medication, treatment, or change to your healthcare should be undertaken based on this content without first consulting a qualified doctor. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition.
Consult Dr. Ruby Rashmi
Specialist Obstetrician & Gynecologist, Dubai
