| Methods |
A double‐blind, RCT. |
| Participants |
By simple random sampling, 250 women from 2 urban hospitals and 1 rural community in Pakistan at 10‐16 weeks' gestation were recruited. 242 women completed the study. The mean (SD) age of the women was 25.7 (4.8) years (range 16–4). Women with known systemic disease were excluded. Serum zinc at enrolment was mean 71.51 µg/dL (SD 21) in the zinc group and 74.09 (SD 23.2) in the placebo group. |
| Interventions |
The supplement was a 20 mg of zinc sulphate powder capsule filled with glucose and a similar capsule as placebo. The supplement were given to the women from the time of booking to the end of their gestational week. In addition, routine supplements of folic acid and iron given. The dietary zinc intake was taken into account by a food diary and various food items were assigned a score. Women were followed up at monthly intervals by trained staff. Compliance was ensured by health visitors and pills were counted out every month before new supply were issued as to double check the consumption of the medicine.
Zinc: 20 mg elemental zinc (zinc sulphate powder capsule) (n = 121).
Placebo: (n = 121) (capsule); in addition, all women had routine supplements of folic acid and iron. |
| Outcomes |
Maternal outcome
Preterm birth.
Neonatal outcomes
Occipitofrontal circumference;
low birthweight;
abortion/intrauterine death;
birthweight;
length. |
| Notes |
Adherence: about 65% of women had good adherence, which was similar in both groups. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
"simple random sampling with preassigned code." |
| Allocation concealment (selection bias) |
Unclear risk |
Method of allocation concealment not reported. |
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
Women and health workers were blinded to content of medication. |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Not reported but likely to have been done. |
| Incomplete outcome data (attrition bias)
All outcomes |
Unclear risk |
Losses to follow‐up: 15% (actual figures not given, but paper notes that losses were non‐differential). |
| Selective reporting (reporting bias) |
Unclear risk |
The protocol is not available. Not enough information to make this judgement. |
| Other bias |
Low risk |
No apparent risk of other bias. |
