Group B streptococcus
- Recto-vaginal swab at 36 to 37 weeks; carriage in 15 to 30 percent.
- Intrapartum prophylaxis (penicillin G or ampicillin intravenously, cefazolin for a non-anaphylactic allergy, clindamycin or vancomycin by sensitivities) for: a positive swab, GBS bacteriuria in this pregnancy, a prior infant with GBS disease, or unknown status with preterm labour, membranes ruptured 18 hours or more, or maternal fever.
- Not needed for a planned caesarean with intact membranes and no labour.
Screened at the first visit
| Infection | What is done |
|---|---|
| HIV | Antiretroviral therapy throughout; viral load under 50 by delivery allows vaginal birth; neonatal prophylaxis; transmission under 1 percent |
| Hepatitis B | Infant vaccine and immunoglobulin at birth; maternal antiviral in the third trimester if the viral load is high |
| Syphilis | Rising in Canada; benzathine penicillin, the only treatment that prevents congenital syphilis; desensitise if allergic |
| Rubella and varicella immunity | Vaccinate postpartum if non-immune (live vaccines are not given in pregnancy) |
| Asymptomatic bacteriuria | Treat, because untreated it leads to pyelonephritis in 20 to 30 percent |
| Chlamydia and gonorrhoea | Universal or risk-based per programme; treat and retest |
Others to know
- Genital herpes: suppressive acyclovir from 36 weeks for those with a history; active lesions or prodrome at labour is an indication for caesarean. A first episode in the third trimester carries the highest neonatal risk.
- Parvovirus B19 (fetal anaemia and hydrops; MCA Doppler surveillance), cytomegalovirus (the commonest congenital infection; hygiene counselling), toxoplasmosis (food and cat litter hygiene), listeria (food safety; a flu-like illness with a fetal loss), Zika (travel history).
- Chorioamnionitis: maternal fever with fetal or maternal tachycardia, uterine tenderness or purulent fluid; antibiotics and delivery.
- Influenza, COVID-19, Tdap and RSV vaccination in pregnancy protect mother and infant.