Title: Incidence and Predictors of Pregnancy among Reproductive-age Women in an ART Clinic
at a Public Health Facility in Arsi Zone, Southeastern Ethiopia: A Five-Year Retrospective
Cohort Study
Version: 2 Date: 19 Sep 2024
Reviewer's report:
This study aims to determine the incidence of pregnancy among women attending ART clinic
in a specific area of Ethiopia. Part of this overarching aim is to assess factors associated with
incident pregnancy. The manuscript as written is difficult to comprehend because the writing
style (English) needs improvement. The language can be improved and the statements to be more
succinct and focused. The main weaknesses of this paper are the following (language concern
aside):
- The sampling frame is not clear --- what are the denominators for the 96.2%. If you have the
entire data and want to examine incidence of pregnancy why take a sample --- if the data is large
then you can stratify by calendar time. For now it is not clear why you chose 481 participants.
-   No definition is provided for your main outcome - pregnancy (other than yes/no pregnancy).
Is the interest in established pregnancies that have come for delivery at the clinic? Or: pregnancy
as it starts and therefore a woman missed LMP or a pregnancy test was performed to confirm
pregnancy? Evaluating the effect of ART on pregnancy would different things depending on
how pregnancies are counted.
- No clear why KM curves are done. the pregnancy incidence rate is calculated using person
years (PYs) of observation. This is fine but what additional information is provided by KM
estimates. You can stratify the PY-based estimates by the same variables included in the KM
analysis. (The KM curves presented also don't show clear trends.)
- The statistical analyses need further consideration.  Was it possible to show incidence rates
in all women on ART?
- Additionally, unless further explained, this study did not address important biases related
to selection, information and data omissions and possibly incomplete data. These are major
concerns to address before making conclusions and making generalizations.
- Importantly, some critical confounders such as contraceptive use, desire to have children, etc.
were excluded. Why?
- No mention of follow-up rates for the entire sample. Women included in this study could be
very selective and bias the results? In the overall study what is the rate of follow-up. Women
who were enrolled in the ART program, how many came back for follow-up visits? If this cannot
be ascertained this data set might not be appropriate for this analysis.
- The measurement issues are not addressed well. How were these variables (include pregnancy
as stated above) defined and measured? Were there missing data?
- The conclusion is rather general and not exactly based on the findings.
Some specific comments:
- Better use the term vertical transmission instead of MTCT of HIV. Throughout the manuscript
there is heavy emphasis of rates of vertical transmission and also reporting rates that are now
historical (e.g., 45%). Better remove these or provide more reasoning why it is important for
this paper.
- In the Abstract and Results there are some discrepancies in the interpretation or presentation
of the findings - e.g., it will clear and informative to say the pregnancy rate or risk of pregnancy
was lower for women age35 or more, etc.
- Several sentences throughout the manuscript are difficult to understand - e.g., lines 70-74 ....
- Line 115: what is chronic follow-up?
- Line 136: what is "N" here?
- Line 139 and throughout Methods - line 142, line 151, line 163, etc.: "will be included" is not
correct (should say "were"- you are analyzing secondary data already collected.
- Line 150 Sampling procedure should be before Sample size determination --- line 144.
- Line 166-167: sentence not complete.
- Line212: Reference here is to WHO clinical staging of 1-4?
- Line 218 --- Women not Women's