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Background: Recent studies have identified HIV as a leading contributor to preterm delivery and its associated morbidity and mortality. However little or no information exists in our sub-region on this subject. Identifying the factors associated with preterm delivery in HIV positive women in our country and sub-region will not only prevent mother to child transmission of HIV virus but will also reduce the morbidity and mortality associated with prematurity and low birth weight. This study was designed to determine the incidence and risk factors for preterm delivery in HIV positive Nigerians.Method: The required data for this retrospective study was extracted from the data base of a cohort study of the outcome of prevention of mother to child transmission at the Nigerian Institute of Medical Research, Lagos. Only data of women that met the eligibility of spontaneous delivery after 20 weeks of gestation were included. Ethical approval was obtained from the Institution’s Ethical Review Board.Results: 181 women out of the 1626 eligible for inclusion into the study had spontaneous preterm delivery (11.1%). The mean birth weight was 3.1 ± 0.4 kg, with 10.3% having LBW. Spontaneous preterm delivery was found to be significantly associated with unmarried status (cOR: 1.7;1.52-2.57), baseline CD4 count <200 cells/mm3(cOR: 1.8; 1.16-2.99), presence of opportunistic infection at delivery (cOR: 2.2;1.23-3.57), multiple pregnancy (cOR 10.4; 4.24 – 26.17), use of PI based triple ARV therapy (eOR 10.2; 5.52 – 18.8) in the first trimester (cOR 2.5; 1.77 – 3.52) on univariate analysis. However after multivariate analysis controlling for potential confounding variables including low birth weight, only multiple pregnancy (aOR: 8.6; CI: 6.73 – 12.9), presence of opportunistic infection at delivery (aOR: 1.9; CI: 1.1 – 5.7), and 1st trimester exposure to PI based triple therapy (aOR: 5.4; CI: 3.4 – 7.8) retained their significant association with preterm delivery.Conclusion: The spontaneous preterm delivery rate among our cohort was 11.1%. HIV positive women with multiple pregnancies, symptomatic HIV infection at delivery and first trimester fetal exposure to PI based triple therapy were found to be at risk of spontaneous preterm delivery. Early booking and non-use of PI based triple therapy in the first trimester will significantly reduce the risk of preterm delivery. © 2012 Ezechi et al.; licensee BioMed Central Ltd.
The study was conducted at the HIV treatment centre, Nigerian Institute of Medical Research, Lagos. The centre started operation in 2002 following the commencement of the Federal Government of Nigeria ARV access programme. It was included in the 25 centres across the country to give research back up to the national ARV access programme. In 2004 it became one of the centers supported by the Harvard School of Public Health (HSPH), Boston through the PEPFAR Fund. The centre currently provides comprehensive, HIV care, treatment and support for 16, 679 patients (64.6% are women). Sixty five percent of the patients come from Lagos and the rest from the other 5 states of southwestern Nigeria as well as from north-central, south-south and south-eastern Nigeria. A little over 0.025% comes from the neigbouring West African countries. No user fee is charged at the centre. Patients are enrolled into the HIV treatment programme following a referral from the HIV Counseling and Testing Centre, Nigerian Institute of Medical Research Lagos or transfer from other government of Nigeria HIV treatment centres. HIV positive pregnant women are seen and registered for PMTCT services at the Wednesday PMTCT clinic. While the antenatal and postnatal services, including infant post exposure prophylaxis are provided by the centre, the intrapartum care is provided in collaboration with Lagos University Teaching Hospital, Idi Araba; Lagos State University Teaching Hospital, Ikeja; General Hospitals Surulere, Apapa, Ikorodu; Havana Specialist Hospital Surulere; Rao Specialist Hospital Surulere, and a number of Catholic mission and private hospitals. Health workers from these centres have been trained on intrapartum care of HIV positive mothers either by our centre, the state or national HIV programme. The mothers are referred to any of the centres nearest to their place of residence at 36 weeks or as soon as possible with detailed information about their chosen mode of delivery, infant feeding choice, and Viral Load and CD4 count results. Infant post exposure drug and mothers ARV drugs are also given to the women. After their delivery at the facility, the women are referred back to our centre at 2 weeks post-delivery with a completed Case Record Form (CRF) designed specifically to capture all delivery related information. Information on the CRF is used to complete the postnatal data base. The home based care team contacts any mother who does not report back to centre at 2 weeks post expected date of delivery to ascertain the reasons for the default. All HIV positive women enrolled into our PMTCT programme between July 2004 and June 2010 that met the eligibility criteria were included into the study. Eligibility criteria for this study was based on the WHO definition of viability, that is a birth weight of ≥ 500 g and born at ≥ 20 weeks of gestation. Gestational age was estimated by the number of days between the first day of the last menstrual period (LMP) and date of birth expressed in completed weeks after LMP. A preterm birth was defined as births of infants occurring at less than 37 completed weeks of gestation. Cases of preterm births as a result of medical/therapeutic indications were excluded. Births without information on vital status, birth weight and gestational age were excluded. Antiretroviral drug regimen used during the study period changed over time as a result of the change in national PMTCT guidelines. The regimen changed thrice between July 2004 and June 2010. From July 2004 till March 2006, because of non-availability of widely accepted Nigerian national PMTCT guideline, HAART based regimen was used for PMTCT except for women who presented in labour who were given single dose Nevirapine with Combivir (Zidovudine and Lamivudine) tail of seven days. Between March 2006 and December 2009, the then national PMTCT guideline was nationally adopted and our centre switched to the dictates of the guideline. Triple ARV therapy (HAART) was used only for women eligible for it based on the clinical stage of their HIV disease or CD4 count less than 200 cell/mm3. Those with CD4 count above 200cells/mm3 were placed on ART prophylaxis of either monotherapy (Zidovudine) or dual therapy (Zidovudine + Lamivudine) depending on the gestational age at booking. From January 2010 we reverted back to triple ARV based regimen for all women as the national guideline was revised in line with WHO recommendation. While NNRTI based HAART was given to women with CD4 counts less than 350 cells/mm3, PI based HAART was prescribed for women with CD4 cell count of ≥ 350 cells/mm3. Information on all HIV positive pregnant women who completed PMTCT services during the study period and met the eligibility criteria was extracted from the centres PMTCT Data base which was collected prospectively. For each birth we extracted information on the date of birth, booking status, maternal age and parity, height and weight, marital status, previous obstetric history, estimated gestational age, birth weight, sex and vital status of the baby at birth and whether the infant was a single or multiple delivery. Information on CD4 count, viral load, opportunistic infection status at delivery, type of ARV drug regimen, time of intiation of triple ARV and duration was also collected. A mother was considered as ‘booked’ if both her pregnancy and HIV status were assessed; laboratory results reviewed and decision taken on the management of her pregnancy. Social status classification by Olusanya and colleagues [16] which was validated for use for the classification of social status of Nigerian women was used. In this system women were classified to belong to one of 5 social classes based on a combination of their educational status and the occupation of their spouse (Class I – V). While classes I and II denote upper social class, classes III and IV, and class V represent middle and lower social classes respectively. A total of 1843 pregnant HIV positive women booked for PMTCT services during the period with 96.2% (1789) completing the PMTCT services. A total of 1812 babies were delivered by the 1789 women, comprising of 1766 singleton and 23 twin deliveries. One hundred and sixty three cases were excluded from the 1789 (9.3%) births because gestational ages were less than 20 weeks (11.0%), information on birth weight, and gestational age was missing because they delivered outside a hospital facility (34.4%), no vital status information (16.6%), baby weighed less than 500 g despite the LMP date given by the women (14.4%), did not give consent for their data to be uploaded (1.8%), viral load and CD4 results could not be traced (19.0%) and estimated gestational age above 46 weeks (2.5%) but birth weights less than 2.5 kg. Frequency distributions were generated and univariate analysis using relevant statistics was performed to identify factors associated with spontaneous preterm delivery. Multivariate logistic regression was used to identify independent risk factors for preterm births while controlling for potential confounders including low birth weight, stage of HIV disease, reproductive tract infection and medical disorders. Variables were entered into the model if their P value on univariate analysis was 0.25 or less. The variable with the strongest association in the univariate model was estimated first, followed by others in descending order. In the analysis, the comparison group was term deliveries (a birth at 37–42 completed weeks of gestation). P < 0.05 was considered to be statistically significant. Odds Ratios (OR) and 95% Confidence Intervals (CI) for the OR were also calculated. Approval for the study was obtained from the Institutional Review Board, Nigerian Institute of Medical Research, Lagos Nigeria. Written informed consent was obtained from all women for the use of their data for study. However women who declined consent to participate in the study were provided care but excluded from research. The clinic patients are organized into an independent support group of people living with HIV (Positive Life Organization of Nigeria) that ensures that patients are not stigmatized and discriminated against. This group ensures that no patient is denied requisite care because of failure to participate in any of our studies including this study.
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