Third Trimester Preparation
Current Guidance Update
Group B Streptococcus Screening
Group B Streptococcus (GBS) screening is recommended between 35–37 weeks, with intrapartum antibiotic prophylaxis advised for GBS-positive women.
Reduced Fetal Movements
Women should contact their maternity unit immediately if they perceive reduced fetal movements from 28 weeks onwards.
Antenatal Corticosteroids
Antenatal corticosteroids are recommended for women at risk of preterm birth between 24–34 weeks to improve neonatal outcomes.
Planned Birth at 39 Weeks
A planned birth at 39 weeks should be discussed for women with a previous caesarean section to support informed birth planning.
Third Trimester Preparation
Third Trimester Antenatal Schedule
Routine Assessment
• Full Blood Count (FBC)
• Antibody Screen
• Anti-D Administration
• Blood Pressure Check
• Urinalysis
• Symphysis-Fundal Height (SFH)
Follow-up Visit
• Blood Pressure Measurement
• Urinalysis
• Symphysis-Fundal Height
• Fetal Position Assessment
Pregnancy Review
• Preeclampsia Discussion
• Birth Plan Review
Screening Visit
• Group B Streptococcus (GBS) Swab
• Fetal Presentation Assessment
Wellbeing Assessment
• Blood Pressure Check
• Urinalysis
• Fetal Wellbeing Review
Post-Dates Consultation
• Discussion of Post-Dates Management
• Induction of Labour Planning
Fetal Monitoring and Wellbeing
Serial SFH measurements on a customised growth chart detect fetal growth restriction or macrosomia. Maternal perception of fetal movements is a critical safety indicator — any reduction from a baby's usual pattern from 28 weeks should prompt same-day contact with the maternity team. Women with risk factors for FGR require serial growth scans from 26–28 weeks with Doppler velocimetry.
Gestational Hypertension and Preeclampsia
New-onset hypertension after 20 weeks without proteinuria is gestational hypertension; preeclampsia adds evidence of systemic organ involvement. Management includes antihypertensive therapy, hospitalisation for severe cases, and delivery timing guided by maternal and fetal condition.
Obstetric Cholestasis
Presents with intense pruritus, particularly on the palms and soles, in the third trimester. Diagnosis is confirmed by elevated serum bile acids. Management includes ursodeoxycholic acid and planned delivery before or at 37 weeks.
Preterm Labour
Labour before 37 weeks affects 8–10% of pregnancies. Tocolytic therapy may delay delivery by 48 hours to allow corticosteroid administration. Antenatal corticosteroids are recommended for threatened preterm birth between 24 and 36+6 weeks.
Birth Preparation
Birth Planning
Discuss preferences for pain relief, birth positions, perineal management, delayed cord clamping and immediate skin-to-skin contact.
GBS Screening
Group B Streptococcus (GBS) screening is recommended between 35–37 weeks, with intrapartum penicillin offered for positive results.
Fetal Presentation
Fetal presentation should be confirmed at 36 weeks, with External Cephalic Version (ECV) offered for breech presentation where appropriate.
Mode of Delivery
An informed discussion should cover vaginal birth after caesarean (VBAC) versus repeat caesarean section for women with a previous caesarean birth.
Frequently Asked Questions
When should I go to hospital in labour?
For first labours, generally when contractions are regular, lasting approximately 60 seconds, occurring every 3–4 minutes for at least an hour. Individualised thresholds should be discussed for women with risk factors.
What is reduced fetal movement and what should I do?
Any perceived reduction or change in your baby's usual pattern requires same-day assessment — do not wait until the next day.
Is induction of labour safe?
Induction at 41 weeks is recommended to reduce stillbirth risk associated with post-dates pregnancy. Risks and benefits are discussed individually.
Conclusion
The third trimester is the culmination of months of physiological change and clinical monitoring. Prepared, informed, well-supported women approach labour and birth with greater confidence and demonstrate better outcomes.
Sources & References
This article draws on guidance current at the time of writing from the following bodies and publications:
- ACOG (2024)
- RCOG GTG 31 (2022)
- WHO (2024 ANC Model)
- NICE NG201 (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
