Changes in the ninth month of pregnancy

The mother’s body prepares for dilation

In the ninth month of pregnancy, the pregnant woman's body prepares for labour. The baby will already be positioned and it is likely that the already bulky belly will look lower. Some women expel the mucus plug days before giving birth.

Changes in the mother

Noveno mes de embarazo

A small amount of bleeding may occur over the course of the last few weeks. This is cervical bleeding due to the dilation of the cervix by the onset of contractions. The beginning of dilation can also cause the mucus plug to be expelled (clear or brown sticky discharge). This does not mean labour will take place straight away, it may still take some time.

The estimated due date (EDD) is 40 weeks into pregnancy, however, it can extend to week 41 or 42. At this point, the pregnancy is prolonged or overdue and, if the baby has not been born naturally, the mother must be admitted to hospital to induce labour to avoid possible complications.

Physical changes

  • Because of the foetus' s position in the birth canal (between the pelvic bones), the belly is in a lower position and pain in the sides gives way to pubic pain. The feeling of tiredness and heaviness is increased.
  • The uterus reaches the base of your breast bone or sternum.
  • The total weight gain throughout the pregnancy is between 11 and 15 kg.

Changes in the baby in the ninth month of pregnancy

  • By the 40th week, the foetus weighs around 3,350 g and is 48-52 cm long.
  • From the 37th week onwards, the foetus is no longer considered a premature baby, it is ready for life outside the womb. 
  • All its organs are already mature and, due to its size, it has hardly any space to move around inside the uterus.
  • During this period, the placenta transfers maternal antibodies to the foetus to provide greater protection against infection at birth.



Dr. Miguel Ángel Herráiz
Head of the Gynaecology Service of Hospital Clínico San Carlos (Madrid)