Dear Doctor, I am 22 years old and have a normal period that lasts 4 days. However, I do not understand safe days or when I’m ovulating. When is the most likely time I can get pregnant? Lisa Dear Lisa, The menstruation and ovulation of a woman are determined by the balance of two hormones, estrogen and progesterone. Usually, menstruation begins around puberty (menarche) and continues till menopause. Ovulation starts to occur a few months to years after menstruation. Normally, after ovulation, the inner wall of the uterus is built up in preparation to receive the fertilised ovum; this entails the coming up of new vasculature. When fertilisation does not occur, this vasculature is broken down, resulting in menstrual bleeding. This cycle of ovulation, menstruation, known as menstrual cycle, is usually set to 28 to 30 days plus/minus one week for the majority of women. It can be variable, physiologically or due to hormonal disorders in some women. Ovulation is said to occur between 14th day (first day of menstrual bleeding is counted as first day) to 21st day of the cycle. Days of ovulation can be judged by the rise in basal body temperature (BBT), that is, increased body temperature in the morning. For this purpose, one can sleep with a thermometer by the bedside. Immediately after getting up, oral temperature can be recorded. The body temperature is slightly elevated during days of ovulation. Ideally, a basal body temperature chart can be prepared. A woman can start marking her temperature every day from the first day of her menstrual cycle. The days the temperature is slightly elevated indicate ovulation days. Over months, one can know accurately, when ovulation occurs in her cycle. The pattern of cervical mucus (sticky fluid coming from lower end of uterus) also changes with ovulation. It becomes thick like raw egg white. Normally, it can be felt easily by fingers. This occurs from a day or two before ovulation, till two days after. Ultrasound examination of the uterus helps to pinpoint the day when an egg is released from the ovary. Serial ultrasound examinations are done from the approximate days of suspected ovulation, till ovulation actually occurs. Chances of pregnancy are much higher if one does intercourse during the days of ovulation. The most fertile period is from about three days before ovulation to one day after. Other days are comparatively safe, that is, risk of getting pregnant is much lower. However, the days of ovulation are not hard and fast. In women with irregular menstrual cycles, it becomes difficult to determine. It is said that ovulation can even occur any time, when one is sexually excited, irrespective of the days of menstrual cycle. Dr Rachna is a specialist in internal medicine at Ruhengeri Hospital rachna212002@yahoo.co.uk
