This study aims to evaluate the effectiveness of a daily Fiber Nutritional Supplement (Materna® Opti fiber), containing partially hydrolyzed guar gum (PHGG) and vitamins C, D, zinc, and selenium, combined with nutritional counselling, for the management of constipation during pregnancy. Constipation is a common gastrointestinal complaint in pregnancy and may negatively affect quality of life and well being.

The study is designed as an open label, single arm intervention conducted in pregnant women between 13 and 27 weeks of gestation who meet the Cullen 2007 criteria for functional constipation. A total of 31 participants are planned for enrolment. Eligible participants will receive one sachet per day of the Fiber Nutritional Supplement (Materna® Opti fiber), providing approximately 5.8 g of PHGG, for a duration of 4 weeks. In addition to the investigational product, all participants will receive standardized constipation counselling at baseline, including education on constipation, lifestyle measures.

Inclusion Criteria:

1. Pregnant women aged 21 years-old or above at recruitment

2. Gestational age of 13-27 weeks at recruitment

3. Singleton pregnancy at recruitment

4. Suffering from functional constipation according to the Cullen 2007 criteria which must include ALL the following and the criteria must be fulfilled for at least two weeks with symptom onset during pregnancy:

   1. Low frequency of stool (<3/week)
   2. Hard stools
   3. Difficulty on evacuation

5. Able to understand and to sign a written Informed Consent Form (ICF) prior to study enrolment.

6. Willing and able to comply with the requirements for participation in this study

7. Willing and able to refrain from consuming other supplements containing fiber, prebiotics, or probiotics other than the Fiber Nutritional Supplement (Materna® Opti-fiber) over the intervention period

8. Able to respond to questionnaires in English

Exclusion Criteria:

1. Treated for constipation less than one week before the start of the study
2. Use of prebiotics or probiotics containing supplements two weeks prior to the study start
3. Major complications during pregnancy e.g., pre-eclampsia, gestational diabetes requiring insulin intervention, severe intra-uterine growth restriction (IUGR), fetal anomalies that in the opinion of the investigator may interfere with the pregnancy and participation in the clinical trial
4. Pre-existing medical conditions e.g., hypertension, diabetes mellitus, thyroid diseases, autoimmune diseases such as Systemic Lupus Erythematosus, antiphospholipid syndrome and other major chronic illness that in the opinion of the investigator may interfere with the pregnancy and participation in the clinical trial
5. Not willing and/or not able to comply with the study procedures and requirements
6. Known serious food allergy
7. Known or suspected history of allergy or intolerance to the investigational product (IP)
8. Active participation in another clinical trial or on-going observational study
9. Family or hierarchical relationships with the research team members