Here is the design of a clinical trial:

Official Title: Nutritional Support and Prophylaxis Doses of Azithromycin for Pregnant Women to Improve Birth Outcomes in the Peri-urban Slums of Karachi, Pakistan -a Randomized Controlled Trial

Included conditions:
- Undernutrition

Study Armgroups:
- {'label': 'Control Arm', 'type': 'NO_INTERVENTION', 'description': 'Arm-A: Standard antenatal care (ANC) counseling, service provision and nutrition counseling (World Health Organization (WHO) standard)'}
- {'label': 'Nutrition only Arm', 'type': 'EXPERIMENTAL', 'description': 'Arm-B:Balanced-energy protein (BEP), ready-to-use utrition supplement for at least 6 months + Standard ANC counseling, service provision and nutrition counseling (WHO standard)', 'interventionNames': ['Dietary Supplement: Balanced-energy protein (BEP)']}
- {'label': 'Nutrition plus Azithromycin Arm', 'type': 'EXPERIMENTAL', 'description': 'Arm-C:Balanced-energy protein (BEP), ready-to-use nutrition supplement for at least 6 months + 2000 mg of Azithromycin at week 20 and 28 of pregnancy + Standard ANC counseling, service provision and nutrition counseling (WHO standard).', 'interventionNames': ['Dietary Supplement: Balanced-energy protein (BEP)', 'Drug: Azithromycin Tablets']}
- {'label': 'Nutrition plus Choline and Nicotinamide Arm', 'type': 'EXPERIMENTAL', 'description': 'Arm-D: Balanced-energy protein (BEP), ready-to-use nutrition supplement for at least 6 months + Choline 450 and Nicotinamide 100 mg (1 each once daily orally starting from week 20 until birth outcome) + Standard ANC counseling, service provision and nutrition counseling (WHO standard).', 'interventionNames': ['Dietary Supplement: Balanced-energy protein (BEP)', 'Drug: Azithromycin Tablets', 'Drug: Choline Bitartrate', 'Drug: Nicotinamide']}

Interventions:
- {'type': 'DIETARY_SUPPLEMENT', 'name': 'Balanced-energy protein (BEP)', 'description': 'Pregnant women in the intervention arms will receive approximately 800 Kcal/day and around 16-21 gram of protein in a day in the form of ready-to-use supplement.', 'armGroupLabels': ['Nutrition only Arm', 'Nutrition plus Azithromycin Arm', 'Nutrition plus Choline and Nicotinamide Arm'], 'otherNames': ['Ready-to-use-supplementary food (RUSF)']}
- {'type': 'DRUG', 'name': 'Azithromycin Tablets', 'description': 'Pregnant women randomized in Arm C will received two doses of 2000 mg of Azithromycin (4 tablets of 500 mg) oral at week 20 and 28 of pregnancy.', 'armGroupLabels': ['Nutrition plus Azithromycin Arm', 'Nutrition plus Choline and Nicotinamide Arm'], 'otherNames': ['Zetro']}
- {'type': 'DRUG', 'name': 'Choline Bitartrate', 'description': 'Pregnant women randomized in Arm D will received 450 mg of Choline orally once daily, starting from week 20 weeks of pregnancy until birth outcome', 'armGroupLabels': ['Nutrition plus Choline and Nicotinamide Arm'], 'otherNames': ['Choline']}
- {'type': 'DRUG', 'name': 'Nicotinamide', 'description': 'Pregnant women randomized in Arm D will received 100 mg of Nicotinamide orally once daily, starting from week 20 weeks of pregnancy until birth outcome', 'armGroupLabels': ['Nutrition plus Choline and Nicotinamide Arm']}

Primary Outcomes:
- {'measure': 'Birth weight of newborn', 'description': 'Weight of the newborn assess in gram to assess the difference among four arms', 'timeFrame': 'To be assessed within 72 hours of birth'}

Please estimate the sample size based on the assumption: 
1-tailed hypothesis testing, significance level of 2.5%, 21% dropout rate, 80% power, family-wise error rate of 0.05, Bonferroni method for three comparisons, alpha of 0.017.
Sample size
        The sample size is calculated via permutation and subsequent adjustment for three comparisons between arms, i.e., intervention arms with control. Improved perinatal outcomes are hypothesized with the supplement of BEP alone or co-administration of BEP supplement with azithromycin as well as with nicotinamide and choline. Thus, the sample size estimated per arm is based on 1-tailed hypothesis testing of birth weight as the primary outcome, a significance level of 2.5% to account for multiple comparisons, and initial assumption of dropout proportion of 21% of study participants assumed in the trial. For birth weight (the primary outcome), it is assumed that the mean difference will be at least 100 g [30]. In order to achieve a test power of 80% and maintain family-wise error rate (FWER) of 0.05; Bonferroni method for three comparisons, alpha of 0.017, and an estimated sample size of 370 pregnant women per arm was attained. A 21% dropout rate was thereafter considered on account of miscarriages, stillbirths, early neonatal deaths, losses to follow-ups, and missed birth assessments due to varying on-field challenges owing to the pandemic. Hence, the sample size was thereafter adjusted to 471 pregnant women in each arm making up a total of 1884 pregnant women for this trial.