Regularity of the Monthly Cycle & Conception

Vitabiotics | Published: 06/09/2019

Regularity of the Monthly Cycle & Conception

Advice from Dr. Michael Dooley (NHS Consultant Gynaecologist)

Michael Dooley, a NHS Consultant Gynaecologist, Fellow of the Royal College of Obstetricians and Gynaecologists and Medical Director of the Poundbury Clinic which uses Pregnacare, gives the following advice.

"Having a regular menstrual cycle is important evidence to demonstrate that your body is working normally. The average menstrual cycle is 28 days long but can range from 24 to 35 days1."

"It's important to note that some women can in fact experience irregular cycles when coming off the contraceptive pill and this can last for up to six months2."

"The menstrual cycle can also be disturbed by factors such as weight loss, weight gain, excessive amount of exercise, physical or emotional upset. It has been suggested that stress can play a role in upsetting the menstrual cycle. If you are concerned about your menstrual cycle it is recommend that you consult your doctor."

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Scientific Reviews on Pregnacare Conception and the Monthly Cycle

A scientific review was carried out by senior obstetrician Prof Mark Brincat FRCOG, FRCPI, an expert in this area, to assess whether the regular use of Pregnacare Conception may be attributed to irregularities in the menstrual cycle. Vitabiotics played no role in the literature review process, in the assessment or writing of the expert report. The conclusion of this report (25 February 2019) states:

There is no evidence that the various components in Pregnacare Conception should cause an irregularity in cycle in normal cycling women. Its various components have been shown to be safe and of benefit.

Therefore, any irregularity in cycle whilst someone is on Pregnacare Conception is likely to be a chance finding and likely to highlight some other pre-existing condition. This warrants referral to a doctor and full investigation.

Further research has also been conducted by way of a systematic review of the effect of nutritional supplementation on menstrual cycle regularity by Dr Kathy Redfern BSc, MSc, PhD, RNutr Lecturer in Nutrition and Dr Gail Rees BSc, PhD, RD, RNutr Associate Professor of Human Nutrition, University of Plymouth.

The report (18 January 2021) concluded:

On the basis of this review, no evidence was found in the literature to suggest that any nutrients contained in Pregnacare® Conception disturb regularity or delay the menstrual cycle.  

(This report has been conducted independently by the authors (Dr Kathy Redfern and Dr Gail Rees. Vitabiotics supported this research, but has played no role in the literature review process, interpretation of the results or writing of the report).

Pregnacare Conception is a carefully formulated, moderate level multi-vitamin and mineral pregnancy supplement, and is free from any drug or hormones. It does not contain any ingredient that is known to cause any delay in the monthly cycle. In fact, one study has clearly shown that the female cycle was more regular during multivitamin supplementation3.

1 NHS.uk states "In most women this happens every 28 days or so. It's common for women to have a cycle that occurs earlier or later than this (24-35 days)."
2 NHS.uk states
"Your periods may be irregular when you first come off the pill, and you should allow up to six months for your natural menstrual cycle to re-establish itself fully. It's quite common to have a longer delay before normal periods start again after stopping the pill".
3 The effect of preconceptional multivitamin supplementation on the menstrual cycle. Randomized Controlled Trial. Dudas I. Rockenbauer M. Czeizel AE. Archives of Gynecology & Obstetrics. 256(3):115-23, 1995.


Please note this should not be regarded as a substitute to the professional medical advice provided by your doctor or other healthcare professionals and we recommend you consult your doctor for specific guidance.


Dr. Michael Dooley (NHS Consultant Gynaecologist)
Dr. Michael Dooley (NHS Consultant Gynaecologist)
Alexandra Phillips

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