The small embryo has now formed into a cluster of cells known as a blastocyst. This blastocyst comes to rest against the side of the uterus and starts to implant about 6 to 7 days after fertilisation. As implantation is taking place this small early embryo sends a signal to the ovary, which continues to secrete the sex hormones progesterone and oestradiol. These hormones keep the endometrium favourable for the early pregnancy to continue. If the egg fails to fertilise, the ovary will stop producing the sex hormones and the endometrium will disintegrate and is shed as a period.
Smoking is also harmful to the developing foetus.
Therefore it is advisable to stop smoking prior to trying to conceive. Alcohol Alcohol in excess can cause problems with both male and female fertility. A modest alcohol intake is reasonable. Again, high alcohol intake during pregnancy can cause foetal abnormality. All women trying to conceive should consider taking this small daily dose of folic acid.