Table 5.

The estimated impact of various infections on adverse outcomes of pregnancy^a through their effect on preterm birth

Maternal infection/ organism	Approximate maternal prevalence (%)	Mothers infected (no.)	Estimated increase in preterm birthb (×)	Estimated excess preterm birthc (no.)	Adverse outcomes linked to preterm birthd
					Perinatal death (no.)	Neurologic sequelae (no.)
Bacterial vaginosis	20.0	800,000	2×	80,000	4000	4000
Chlamydia	5.0	200,000	2×	20,000	1000	1000
Cytomegalovirus	33.0	1,300,000	e	—	—	—
Gonorrhea	1.0	40,000	3×	8,000	400	400
Group B streptococcus	20	80,000	e	—	—	—
Hepatitis B	1.0	40,000	e	—	—	—
Herpes simplex	20.0	800,000	e	—	—	—
HIV	0.2	8000	e	—	—	—
Rubella	0	0	e	—	—	—
Syphilis	0.12	4800	2×	480	24	24
Trichomonas	2.0	80,000	1.3	2400	120	120

Data from Refs. [75], [135].

^aAssuming 4,000,000 births per year.

^bBased on best available data in untreated women.

^cAssuming a baseline preterm rate of 10%.

^dAssuming 5% deaths and 5% neurologic sequelae.

^eInsufficient evidence for a causative relationship.