Obstetrics — Common Presentations
Pre-conception counselling
Overview and approach
Pre-conception care identifies and modifies medical, behavioural and social risks before pregnancy; ideally provided by the woman's usual GP, giving the chance to screen and advise on conception and early pregnancy care (1). Every woman of reproductive age should be considered, given high rates of unplanned pregnancy; the 'One Key Question' approach asks 'Would you like to become pregnant in the next year?' (1).
- About 40% of pregnancies in Australia are unintended (1).
Assessment and clinical features
- Assess and stabilise pre-existing medical and mental health conditions; review all medicines (prescribed, over-the-counter, supplements) for teratogenicity and switch to safer alternatives where required (1).
- Maternal age: fertility falls and chromosomal abnormality and miscarriage risk rise with age (1).
- Weight and nutrition: assess BMI and micronutrient reserves, especially if adolescent or closely spaced pregnancies (interpregnancy interval under 6 months) (1).
- Substance use: ask about smoking, alcohol and illicit drugs (below).
Differentials and investigations
- Reproductive carrier screening (cystic fibrosis, SMA, fragile X) is recommended to anyone planning pregnancy; genetic counselling for couples at increased risk of a heritable disorder (e.g. haemoglobinopathies, family history of breast/ovarian/colon cancer, familial hypercholesterolaemia, haemochromatosis) (1).
- Vaccination history: update COVID-19, measles, mumps, rubella, varicella, diphtheria/tetanus/pertussis; consider hepatitis B, rubella and varicella immunisation if immunity incomplete (1). Need for rubella, varicella and pertussis immunisation (uncertain = serology).
- Live attenuated viral vaccines: avoid conception for 28 days after administration.
- Influenza vaccine recommended. Routine cervical screening if due (see Cervical Screening page).
Management and follow-up
- Folic acid at least 0.4 mg (400 microg) daily for at least one month before conception and for the first 3 months of pregnancy (1). Use 5 mg daily where neural tube defect risk is increased: anticonvulsants, pre-pregnancy diabetes, previous child/family history of NTD, BMI over 30 (1).
- Iodine 150 mcg daily, started before planned pregnancy or as soon as pregnancy is confirmed (1). Iodine supplementation is especially important in regions of dietary deficiency. Thyroid disease needs individualised advice.
- Maternal medications reviewed and optimised; specialist referrals as needed; nutritious diet and exercise.
- Alcohol: women who are pregnant or planning pregnancy should not drink alcohol; counselling and pharmacotherapy for alcohol/substance use for either parent (1).
- Alcohol in pregnancy: fetal alcohol syndrome (growth retardation, structural and facial defects, joint abnormalities, cardiac defects) and neurodevelopmental and behavioural effects.
- Smoking: identify smokers (and partners) early, offer cessation (1). CO reduces fetal oxygen delivery, nicotine causes uteroplacental vasoconstriction and placental change, low birth weight; increased perinatal mortality.
- Illicit drugs: heroin (IUGR, mortality, preterm labour); amphetamines (miscarriage, preterm birth, growth restriction, abruption, fetal death); cocaine (arrhythmia, CNS damage, abruption, growth restriction, preterm labour); cannabis (risks regardless of tobacco use).
- Indirect effects: lifestyle adversity and malnutrition.
- Interpregnancy interval: avoid under 6 months; counsel about risks of conceiving within 18 months, especially after caesarean (1).
- Encourage first antenatal visit early, ideally before 10 weeks (1).
Red flags and clinical pearls
- Anticonvulsants, warfarin, ACE inhibitors, isotretinoin, methotrexate and other teratogens need review before conception.
- High-dose folic acid (5 mg) is a common exam and clinical point (1).
- Link: see Medication in pregnancy and Contraception pages.
References
Last updated from Sen’s notes on 9 October 2026.