Pregnancy outcomes: prevalence estimates
This page provides example prevalence ranges for key pregnancy endpoints of high importance in research on HIV agents used in pregnancy.
- Table 1 provides general population estimates.
- Table 2 provides estimates for women living with HIV.
The estimates were derived preferentially but not exclusively from low- and middle-income countries (LMICs), in particular sub-Saharan Africa, and from studies conducted since 2010. Prevalence estimates were obtained from key pregnancy studies, systematic reviews and meta-analyses, rather than through an exhaustive review of the literature.
Important: These tables are intended to provide reasonable pregnancy outcome estimates to inform sample size calculations for various comparisons and study designs. The estimates should not be taken to be definitive. Where possible, investigators should use the most relevant local estimates (in terms of location, population, calendar year, method of ascertainment and definition) in planning their analyses and their own sample size calculations. Also, prevalence of most of these endpoints differs substantially between populations; hence, consideration of any findings in the context of locally relevant comparator endpoint prevalence data is important, whenever possible. |
Table 1. Pregnancy outcome prevalence ranges for the general population
Outcome | Range (%) |
Miscarriage, <20 weeks’ gestation* | 15%-30%*(1,2) |
Stillbirth (ranging from ≥20 to ≥28 weeks’ gestation) | 0.3%-2.5% (3-7) |
Preterm <37 weeks (in live births) | 6%-22% (4-6,8-12) |
Low birthweight <2,500g (in live births) | 10%-14% (4,5,7,11,12) |
Small for gestational age (SGA) (in live births) | 16%-30% (5,13,14) |
Neonatal death (through 28 days) | 1.7%-3.2% (5,6,9,12,15) |
Infant mortality (through 1 year) | 2.6%-3.1% (15,16) |
Congenital anomalies | 1%-4.3% (12,17-20) |
Congenital anomalies in studies that include only major structural abnormalities of prenatal origin that affect health, survival, physical or cognitive functioning of the individual | 0.4%-0.7 % (21-25) |
Neural tube defects | 8-50 per 10,000 (26-28) |
Maternal mortality (during pregnancy or within 42 days of delivery) | <1%-5% (12,29,30) |
* These estimates are based on data from Europe and North America only; data not available for miscarriage rates <28 weeks’ gestation
Table 2. Pregnancy outcome prevalence ranges for women living with HIV
Outcome | Range (%) |
Miscarriage, <20 weeks’ gestation* | 20%-37%* (31,32) |
Stillbirth (ranging from ≥20 to ≥28 weeks’ gestation) | 1%-4% (7,31,33-37) |
Preterm <37 weeks (in live births) | 6%-22% (4-6,8-12) |
Low birthweight <2,500g (in live births) | 12%-24% (7,34,38,41,43,44) |
Small for gestational age (SGA) | 10%-25% (7,34,37,40,42,43) |
Neonatal death (through 28 days) | 1-4% (33,45,46) |
Infant mortality (through 1 year) | 1-7% (33) |
Congenital anomalies | 2-6% (34,47,48) |
Congenital anomalies in studies that include only major structural abnormalities of prenatal origin that affect health, survival, physical or cognitive functioning of the individual | 0.4%-0.6% (21-25) |
Neural tube defects | 8-50 per 10,000 (21,28,49) |
Maternal mortality (during pregnancy or within 42 days of delivery) | 2%-6% (29,30,33) |
Combined outcome (PTB, SGA, LBW and neonatal death) | 30-35% (50,51) |
*Among persons conceiving on ART (primarily older ARV regimens)
References
- Wilcox AJ, Weinberg CR, O'Connor JF,
et al. Incidence of early loss of pregnancy. N Engl J Med 1988; 319(4):
189-94.
- Quenby S, Gallos ID, Dhillon-Smith
RK, et al. Miscarriage matters: the epidemiological, physical, psychological,
and economic costs of early pregnancy loss. Lancet
2021; 397(10285): 1658-67.
- Hug L, You D, Blencowe H, et al.
Global, regional, and national estimates and trends in stillbirths from 2000 to
2019: a systematic assessment. Lancet
2021; 398(10302): 772-85.
- Lokken EM, Mathur A, Bunge KE, et
al. Pooled Prevalence of Adverse Pregnancy and Neonatal Outcomes in Malawi,
South Africa, Uganda, and Zimbabwe: Results From a Systematic Review and
Meta-Analyses to Inform Trials of Novel HIV Prevention Interventions During
Pregnancy. Front Reprod Health 2021; 3.
- Chasekwa B, Ntozini R, Church JA, et
al. Prevalence, risk factors and short-term consequences of adverse birth
outcomes in Zimbabwean pregnant women: a secondary analysis of a
cluster-randomized trial. Int J Epidemiol
2022; 51(6): 1785-99.
- Zimbabwe Healthy Newborn Network.
2024. https://www.healthynewbornnetwork.org/country/zimbabwe/
(accessed 18 January 2024).
- Cutland CL, Sawry S, Fairlie L, et
al. Obstetric and neonatal outcomes in South Africa. Vaccine 2024.
- Ohuma EO, Moller AB, Bradley E, et
al. National, regional, and global estimates of preterm birth in 2020, with
trends from 2010: a systematic analysis. Lancet
2023; 402(10409): 1261-71.
- Sharan A, Stuurman AL, Jahagirdar S,
et al. Estimating baseline rates of adverse perinatal and neonatal outcomes
using a facility-based surveillance approach: A prospective observational study
from the WHO Global Vaccine Safety Multi-Country Collaboration on safety in
pregnancy. EClinicalMedicine 2022; 50: 101506.
- Chawanpaiboon S, Vogel JP, Moller AB,
et al. Global, regional, and national estimates of levels of preterm birth in
2014: a systematic review and modelling analysis. Lancet Glob Health 2019; 7(1): e37-e46.
- Pusdekar
YV, Patel AB, Kurhe KG, et al. Rates and risk factors
for preterm birth and low birthweight in the global network sites in six low-
and low middle-income countries. Reprod
Health 2020; 17(Suppl 3): 187.
- Balkus JE, Neradilek M, Fairlie L, et
al. Assessing pregnancy and neonatal outcomes in Malawi, South Africa, Uganda,
and Zimbabwe: Results from a systematic chart review. PLoS One 2021; 16(3):
e0248423.
- Lawn JE, Ohuma EO, Bradley E, et al.
Small babies, big risks: global estimates of prevalence and mortality for
vulnerable newborns to accelerate change and improve counting. Lancet 2023; 401(10389): 1707-19.
- Lee AC, Katz J, Blencowe H, et al.
National and regional estimates of term and preterm babies born small for
gestational age in 138 low-income and middle-income countries in 2010. Lancet Glob Health 2013; 1(1): e26-36.
- United Nations Inter-Agency Group for
Child Mortality Estimation (UN IGME). Levels and trends in child mortality,
2021. Available from: https://data.unicef.org/resources/levels-and-trends-in-child-mortality-2021/
(accessed 18 January 2024).
- The World Bank. Mortality rate, infant
(per 1000 live births). 2021. https://data.worldbank.org/indicator/SP.DYN.IMRT.IN
(accessed 18 January 2024).
- EUROCAT. Prevalence charts and tables,
2005-2021, 2023. Available from: https://eu-rd-platform.jrc.ec.europa.eu/eurocat/eurocat-data/prevalence_en
(accessed 18 January 2024).
- Bhide P, Kar A. A national estimate of
the birth prevalence of congenital anomalies in India: systematic review and
meta-analysis. BMC Pediatr 2018; 18(1): 175.
- Adane F, Afework M, Seyoum G, Gebrie A.
Prevalence and associated factors of birth defects among newborns in
sub-Saharan African countries: a systematic review and meta-analysis. Pan Afr Med J 2020; 36: 19.
- Centers for Disease Control and
Prevention (CDC). Update on overall prevalence of major birth defects--Atlanta,
Georgia, 1978-2005. MMWR Morb Mortal Wkly
Rep 2008; 57(1): 1-5.
- Gill MM, Khumalo P, Chouraya C, et al.
Strengthening the Evidence: Similar Rates of Neural Tube Defects Among
Deliveries Regardless of Maternal HIV Status and Dolutegravir Exposure in
Hospital Birth Surveillance in Eswatini. Open
Forum Infect Dis 2023; 10(9):
ofad441.
- Gill MM, Khumalo P, Chouraya C, et al.
Adverse pregnancy outcomes following dolutegravir transition among women
delivering at surveillance sites in Eswatini.
12th International AIDS Society Conference on HIV Science. Melbourne,
Australia; 2023.
- Mumpe-Mwanja D, Barlow-Mosha L,
Williamson D, et al. A hospital-based birth defects surveillance system in
Kampala, Uganda. BMC Pregnancy Childbirth
2019; 19(1): 372.
- Patel R, Mehta U, Humphrey J, et al.
Dolutegravir exposure and congenital anomalies in sub-Saharan Africa. Conference on Retroviruses and Opportunistic
Infections (CROI) Seattle, Washington, USA; 2023.
- Zash
R, Holmes L, Diseko M, et al. Neural-Tube Defects and
Antiretroviral Treatment Regimens in Botswana. N Engl J Med 2019; 381(9):
827-40.
- Ssentongo P, Heilbrunn ES, Ssentongo
AE, Ssenyonga LVN, Lekoubou A. Birth prevalence of neural tube defects in
eastern Africa: a systematic review and meta-analysis. BMC Neurol 2022; 22(1):
202.
- Zaganjor I, Sekkarie A, Tsang BL, et
al. Describing the Prevalence of Neural Tube Defects Worldwide: A Systematic
Literature Review. PLoS One 2016; 11(4): e0151586.
- Barlow-Mosha L, Serunjogi R, Kalibbala
D, et al. Prevalence of neural tube defects, maternal HIV status, and
antiretroviral therapy from a hospital-based birth defect surveillance in
Kampala, Uganda. Birth Defects Res
2022; 114(3-4): 95-104.
- Bauserman M, Thorsten VR, Nolen TL, et
al. Maternal mortality in six low and lower-middle income countries from 2010
to 2018: risk factors and trends. Reprod
Health 2020; 17(Suppl 3): 173.
- UNICEF. Maternal Mortality. 2023. https://data.unicef.org/topic/maternal-health/maternal-mortality/
(accessed 18 January 2024).
- Stringer EM, Kendall MA, Lockman S, et
al. Pregnancy outcomes among HIV-infected women who conceived on antiretroviral
therapy. PLoS One 2018; 13(7): e0199555.
- Wall KM, Haddad LB, Mehta CC, et al.
Miscarriage among women in the United States Women's Interagency HIV Study,
1994-2017. Am J Obstet Gynecol 2019; 221(4):
347.e1-.e13.
- Lockman
S, Brummel SS, Ziemba L, et al. Efficacy and safety of
dolutegravir with emtricitabine and tenofovir alafenamide fumarate or tenofovir
disoproxil fumarate, and efavirenz, emtricitabine, and tenofovir disoproxil
fumarate HIV antiretroviral therapy regimens started in pregnancy (IMPAACT 2010/VESTED):
a multicentre, open-label, randomised, controlled, phase 3 trial. Lancet 2021; 397(10281): 1276-92.
- Saint-Lary L, Benevent J, Damase-Michel
C, Vayssière C, Leroy V, Sommet A. Adverse perinatal outcomes associated with
prenatal exposure to protease-inhibitor-based versus non-nucleoside reverse
transcriptase inhibitor-based antiretroviral combinations in pregnant women
with HIV infection: a systematic review and meta-analysis. BMC Pregnancy Childbirth 2023; 23(1):
80.
- Favarato G, Townsend CL, Peters H, et
al. Stillbirth in Women Living With HIV Delivering in the United Kingdom and
Ireland: 2007-2015. J Acquir Immune Defic
Syndr 2019; 82(1): 9-16.
- Phiri K, Williams PL, Dugan KB, et al.
Antiretroviral Therapy Use During Pregnancy and the Risk of Small for
Gestational Age Birth in a Medicaid Population. Pediatr Infect Dis J 2015; 34(7):
e169-75.
- Zash
R, Jacobson DL, Diseko M, et al. Comparative Safety of
Antiretroviral Treatment Regimens in Pregnancy. JAMA Pediatr 2017; 171(10):
e172222.
- Tshivuila-Matala COO, Honeyman S,
Nesbitt C, Kirtley S, Kennedy SH, Hemelaar J. Adverse perinatal outcomes
associated with antiretroviral therapy regimens: systematic review and network
meta-analysis. Aids 2020; 34(11): 1643-56.
- Favarato G, Townsend CL, Bailey H, et
al. Protease inhibitors and preterm delivery: another piece in the puzzle. AIDS 2018; 32(2): 243-52.
- European Pregnancy and Paediatric HIV
Cohort Collaboration (EPPICC) Study Group. Nucleoside reverse transcriptase
inhibitor backbones and pregnancy outcomes. AIDS
2019; 33(2): 295-304.
- Delicio AM, Lajos GJ, Amaral E,
Cavichiolli F, Polydoro M, Milanez H. Adverse effects in children exposed to
maternal HIV and antiretroviral therapy during pregnancy in Brazil: a cohort
study. Reprod Health 2018; 15(1): 76.
- Malaba TR, Phillips T, Le Roux S, et
al. Antiretroviral therapy use during pregnancy and adverse birth outcomes in
South African women. Int J Epidemiol
2017; 46(5): 1678-89.
- Snijdewind IJM, Smit C, Godfried MH, et al. Preconception use of cART by HIV-positive pregnant women increases the risk of infants being born small for gestational age. PLoS One. 2018;13(1):e0191389.
- van der Merwe K, Hoffman R, Black V,
Chersich M, Coovadia A, Rees H. Birth outcomes in South African women receiving highly active antiretroviral therapy: a retrospective observational study. J Int AIDS Soc 2011; 14: 42.
- Zash R, Rough K, Jacobson DL, et al.
Effect of Gestational Age at Tenofovir-Emtricitabine-Efavirenz Initiation on
Adverse Birth Outcomes in Botswana. J Pediatric Infect Dis Soc 2018; 7(3):
e148-e51.
- Fowler
MG, Qin M, Fiscus SA, et al. Benefits and Risks of
Antiretroviral Therapy for Perinatal HIV Prevention. N Engl J Med 2016; 375(18):
1726-37.
- Antiretroviral Pregnancy Registry
Steering Committee. Antiretroviral Pregnancy Registry Interim Report for 1
January 1989 through 1 January 2023. Wilmington, NC: Registry Coordinating
Center, 2023. Available from: https://www.apregistry.com/forms/interim_report.pdf
(accessed 18 January 2024).
- Hill A, Clayden P, Thorne C, Christie
R, Zash R. Safety and pharmacokinetics of dolutegravir in HIV-positive pregnant
women: a systematic review. J Virus Erad
2018; 4(2): 66-71.
- Zash R, Holmes LB, Diseko M, et al.
Update on neural tube defects with antiretroviral exposure in the Tsepamo
study, Botswana. International AIDS
Conference. Montreal, Canada; 2022.
- Kreitchmann R, Li SX, Melo VH, et al.
Predictors of adverse pregnancy outcomes in women infected with HIV in Latin
America and the Caribbean: a cohort study. Bjog
2014; 121(12): 1501-8.
- Zash R, Jacobson DL, Diseko M, et al. Comparative safety of dolutegravir-based or efavirenz-based antiretroviral treatment started during pregnancy in Botswana: an observational study. Lancet Glob Health 2018; 6(7): e804-e10.