Accuracy of portable ultrasound for obstetric biometry.

OBJECTIVE: We assessed the accuracy of two portable ultrasound machines (PUM) in obtaining fetal biometry and estimating gestational age. METHODS: We analyzed data from the Fetal Age Machine Learning Initiative, an observational study of pregnant women in the United States and Zambia. Each participant underwent assessment by an experienced sonographer using both a high-specification ultrasound machine (HSUM) and a PUM (either Butterfly iQ or Clarius C3) to measure fetal biometry and calculate estimated gestational age (EGA) at each visit. Through comparison of paired PUM-HSUM scans, we estimated agreement between individual biometry measurements and aggregate gestational age estimates by reporting mean difference, along with intraclass correlation coefficient (ICC) and Bland-Altman plots, adjusting for trend. RESULTS: 881 participants contributed 1386 paired PUM-HSUM ultrasound studies between April and December 2021. PUM studies included 991 Butterfly and 395 Clarius. Gestational age at scan ranged from 7 to 38 weeks. Compared to HSUM, the Butterfly PUM had a mean difference of -0.20 days (95%CI±0.40) in the 1st trimester and -0.68 days (95%CI±0.68) in the 2nd/3rd trimesters. Also compared to HSUM, the Clarius PUM had a mean difference of 0.47 days (95%CI±0.64) in the 1st trimester and -1.67 days (95%CI±0.43) in the 2nd/3rd trimesters. ICCs were 0.989 or greater throughout. Increasing gestational age was associated with increasing error and absolute error. Both PUM devices demonstrated a modest trend toward underestimation of EGA at advancing gestational ages in 2nd/3rd trimester scans, compared to HSUM. CONCLUSION: Both the Butterfly iQ and Clarius C3 PUM devices were highly accurate in performing fetal biometry in a diverse population from the US and Zambia. This article is protected by copyright. All rights reserved.

CD4+ cell count and risk for antiretroviral drug resistance among women using peripartum nevirapine for perinatal HIV prevention.

OBJECTIVE: To determine the association between the antenatal CD4(+) cell count and the development of viral drug resistance following the use of peripartum nevirapine (NVP) for perinatal HIV prevention. DESIGN: Secondary analysis of data from a previously conducted randomised controlled trial. SETTING: Lusaka, Zambia. POPULATION: HIV-positive pregnant women. METHODS: We analysed the data from a clinical trial of single-dose tenofovir/emtricitabine (TDF/FTC) to reduce viral drug resistance associated with peripartum NVP. The trial population was categorised according to antenatal CD4(+) cell count (200-350, 351-500 and >500 cells/µl). MAIN OUTCOME MEASURES: The relative risk for acquiring drug resistance, determined by consensus sequencing and oligonucleotide ligation assay (OLA), was estimated using multivariable logistic regression. RESULTS: Of the 397 study participants, 119 (30%) had a CD4(+) count of 200-350 cells/µl, 135 (34%) had a CD4(+) count of 351-500 cells/µl and 143 (36%) had a CD4(+) count of >500 cells/µl. Among women receiving no intervention, the risk for drug resistance appeared to increase as the CD4(+) cell count decreased. Participants with CD4(+) cell counts of 200-350 cells/µl randomised to the study arm had the lowest risk, suggesting a higher efficacy of the intervention within this stratum. These results were consistent at 2 and 6 weeks, regardless of how drug resistance was measured. CONCLUSIONS: Women with CD4(+) cell counts of 200-350 cells/µl may be at increased risk for viral drug resistance following the use of peripartum NVP. Given the high prevalence of NVP resistance and the clear benefits of treatment, antiretroviral therapy should be initiated among pregnant women with CD4(+) cell counts of ≤350 cells/µl.

Community-based follow-up for late patients enrolled in a district-wide programme for antiretroviral therapy in Lusaka, Zambia.

Timely adherence to clinical and pharmacy appointments is well correlated with favourable patient outcomes among HIV-infected individuals on antiretroviral therapy. To date, however, there is little work exploring reasons behind missed visits or evaluating programmatic strategies to recall patients. For this study we implemented community-based follow-up of late patients as part of a large-scale programme for HIV care and treatment in Lusaka, Zambia. Through a network of local home-based care organizations, we attempted home visits to recall patients using locator information provided at time of enrolment. Between May and September 2005, home-based caregivers were dispatched to trace 1,343 patients with missed appointments. Of these, 554 (41%) were untraceable because the provided address was invalid, the patient had moved or no one was at the home. Of the remaining 789, 359 (46%) were reported to have died. Only 430 (54% of those traced, 32% overall) were contacted directly and encouraged to return for care. The likelihood of patient return was higher among traced patients in crude analysis (relative risk [RR] = 2.5; 95%CI = 1.9-3.2) and in multivariable analysis controlling for baseline body mass index, sex and CD4 + count < or = 50/microL (adjusted RR = 2.3; 95%CI = 1.7-3.2). However, the process was inefficient: one late patient returned for every 18 home visits that were made. Reasons for missed visits were provided in 271 of 430 (63%) of the patients who were successfully traced. Common reasons included feeling too sick to come to the clinic, travelling away from home and being too busy. Despite the availability of free ART in Lusaka, patients face significant barriers to attending scheduled clinical visits. Cost-effective and feasible strategies are urgently needed to improve timely patient follow-up.

Prevalence and distribution of HPV genotypes among HIV-infected women in Zambia.

We screened 145 HIV-infected non-pregnant women at a tertiary care centre in Lusaka, Zambia. Liquid-based cytology and human papillomavirus (HPV) genotyping with PGMY09/11 biotinylated primers (Roche Linear Array HPV genotyping test) maximised sensitivity of cytology and HPV assessments. Among high-risk (HR) types, HPV 52 (37.2%), 58 (24.1%) and 53 (20.7%) were more common overall than HPV 16 (17.2%) and 18 (13.1%) in women with high-grade squamous intraepithelial lesions or squamous cell carcinoma (SCC) on cytology. High-risk HPV types were more likely to be present in women with CD4+ cell counts <200 microl(-1) (odds ratios (OR): 4.9, 95% confidence intervals (CI): 1.4-16.7, P=0.01) and in women with high-grade or severe cervical cytological abnormalities (OR: 8.0, 95% CI: 1.7-37.4, P=0.008). Human papillomavirus diversity in high-grade lesions and SCC on cytology suggests that HPV 16- and 18-based vaccines may not be adequately polyvalent to induce protective immunity in this population.

Mother-to-child HIV transmission prevention in Thailand: physician zidovudine use and willingness to provide care.

We conducted a mail survey of Thai physicians involved in obstetric care to assess attitudes and practices regarding zidovudine use during pregnancy and willingness to provide care for HIV-infected women in 1999. Of 845 respondents, 57% reported using perinatal zidovudine prophylaxis, an increase from 20% reported in 1997. Highest failure-to-use rates (52%) were among the respondents from Central and Southern Thailand and lowest failure rate was among those from the North (37%). Predictors of failure to use zidovudine in a multivariable logistic regression analysis were not knowing a source from which to obtain zidovudine (odds ratio [OR]=3.1), working in smaller hospitals (district/provincial/private hospitals) (OR=2.0), being from Eastern/Central/Southern Thailand (OR=1.4), unwillingness to perform caesarean section delivery on a HIV-positive women (OR=1.8), having provided antenatal care to fewer than 100 women in 1998 (OR=1.7), and unfamiliarity with Pediatric AIDS Clinical Trial Group 076 protocol (OR=2.9). A number of respondents described themselves as unwilling to perform pelvic examinations (15%), vaginal delivery (29%), or caesarean sections (37%) on HIV-infected pregnant women. About 39% of the respondents advocated elective terminations of pregnancy for HIV-infected women. Our survey indicates an increasing willingness of Thai physicians to use antiretroviral therapy to prevent mother-to-child HIV transmission and to provide obstetric care to HIV-infected women. However, availability and affordability remained major barriers to more widespread antiretroviral use in 1999.

Perinatal HIV transmission: developing country considerations.

In many developing countries, because the prevalence of maternal HIV infection is high (more than 30% in some sub-Saharan African countries) and the resources commonly used to prevent transmission in developed countries are generally not available, transmission of HIV from mother to infant is a devastating problem. Countries already experiencing infant mortality rates 10- to 20-fold greater than those in developed countries can expect a doubling of infant and childhood mortality due to HIV. Those infants who escape infection themselves can expect to be orphaned in early childhood. Low-cost antiviral therapy can reduce transmission substantially, but many countries do not have the infrastructure to screen pregnant women for HIV and appropriately treat the mothers and infants. In developing countries, reduction in maternal-child transmission is feasible, but will require substantial additional resources and a well-functioning obstetric care system.