We talk about ‘time of the month’ and periods being affected by the phases of the moon, so a ‘normal’ menstrual cycle must be 28 days, right?  Wrong!  Normal menstrual cycles are much more varied than that – and if you are trying to conceive, the only important fact is the length of your own menstrual cycle and the timing of your own fertile window.

Women are all individual, and so are their menstrual cycles.  Some have very regular cycles, others are highly irregular; some have short cycles, some have long ones.  A study of 1,798 women in England and Wales recorded cycles from as short as 26 days to as long as 38 days.  The researchers also noted that women who had irregular cycles tended to have these balanced out over time, with a long cycle being followed by a shorter one.

A study of 415 premenopausal women aged 22 to 50 in Delhi similarly found that the majority of women had cycles between 25 and 35 days long.  The researchers found that a lower Body Mass Index was related to a longer cycle.  The age at which the women started their periods was also significant: the women who started menstruating later were more likely to have longer cycles.


Carole Gilling-Smith, Consultant Gynaecologist and Medical Director at the Agora Gynaecology & Fertility Centre, explains that if your cycle length is not regular and varies by more than 5 days from one month to the next, you may not be ovulating and your fertility will be affected: “This is where fertility specialists can help – we often have to check for ovulation by carrying out a series of pelvic ultrasound scans of the ovary and uterus during the first part of the menstrual cycle to follow the development of an egg in a tiny sack of fluid in the ovary called a follicle. So-called ‘follicle tracking’ is the best way to establish if ovulation is occurring or whether fertility ‘ovulation induction’ drugs might be needed.”


Our experts at The Agora Clinic are happy to advise you on how you can boost your chances of conceiving – including what measurements you need to be tracking and when you should be having sex!


To find out more about how our fertility experts can help you, call us on

01273 229410