Excess blood loss

Can losing a lot of blood after delivery affect my milk supply?

A big loss of blood (hemorrhage) or big drop in blood pressure during or after delivery may result in the milk coming in late or in a low milk supply. There are many possible reasons for these: a placenta being in the wrong place or too firmly attached, a stretched uterus, high blood pressure, or difficult labour. A hemorrhage or a big blood pressure drop can harm the pituitary gland and a hemorrhage can cause low levels of red blood cells. The mother’s illness may cause mother-baby separation. All these may decrease the milk supply. Mothers with a permanently damaged pituitary gland, a condition called Sheehan syndrome, are very likely to have a permanently low milk supply.

A) Describing a hemorrhage and drop in blood pressure

Losing a lot of blood (hemorrhage) during or after (postpartum) delivery causing a sudden or large drop in blood pressure can cause harm to the pituitary gland and result in mother-baby separation right after birth. Blood loss can cause low red blood cell levels (anemia). These harms can result in the milk coming in late or in low milk supply (Chessman 2018).


B) Causes of a hemorrhage or drop in blood pressure

The risk of a hemorrhage or a drop in blood pressure rises when mothers have:

  • A placenta that:
    • Is in the wrong place and covers the cervix (placenta previa)
    • Is too firmly attached to the uterus (placenta accreta, increta, or percreta)
    • Separates too early from the uterus (abruption)
  • A uterus that is stretched or weakened by:
  • High blood pressure
  • Infection
  • Medication to help labour
  • Difficulties in labour:
    • A long labour
    • Instrument use (forceps, suction)
    • A tear of the uterus, cervix, or other structures
  • Any conditions that keep the blood from clotting

C) Low milk supply and Sheehan syndrome

The pituitary gland is at the base of the brain. It makes and stores many hormones, including prolactin, which stimulates milk production. It doubles in size during pregnancy.

If a mother has a hemorrhage and her blood pressure falls quickly, the front part of the pituitary gland may not receive enough blood and could be temporarily or permanently damaged, resulting in low levels of one or more hormones. Permanent damage in these circumstances is called Sheehan syndrome.

A major drop in blood pressure can result in the milk coming in late. It can also decrease the milk supply. This may be temporary if the effect on the pituitary gland is mild and reversible. Mothers with Sheehan syndrome are most likely to have a permanently low milk supply (Flood et al. 2018). If the damage to the pituitary is severe, they may have no milk at all. We have seen this once in our clinic.

Mothers with Sheehan syndrome may develop health problems including:

  • Irregular periods or no periods
  • Low thyroid hormone levels
  • A poorly functioning adrenal gland
  • Weakness
  • Anemia
  • Low levels of sodium in the blood

It may take a long time, even years, for Sheehan syndrome to be diagnosed (Ramiandrasoa 2013). 

Alternatively some mothers develop significant symptoms shortly after the birth of the baby. These can include severe headache, nausea, vomiting, eye pain cause by light, and confusion (Varutti 2019).

Mothers with a history of large blood loss or a drop in blood pressure during or after delivery and a low milk supply should see their health-care providers. Sheehan syndrome is diagnosed with blood and radiological tests.


Chessman J, Patterson J, Nippita T, et al. Haemoglobin concentration following postpartum haemorrhage and the association between blood transfusion and breastfeeding: a retrospective cohort study. BMC Res Notes. 2018 Oct 1;11(1):686
Flood M, Pollock W, McDonald S, et al. Primary Postpartum Haemorrhage and Breastfeeding for Confinements 2009–13 in Victoria. Paediatr Child Health 2018; 54: 75-75
Ramiandrasoa C, Castinetti F, Raingeard I, et al. Delayed diagnosis of Sheehan's syndrome in a developed country: a retrospective cohort study. Eur J Endocrinol. 2013 Sep 12;169(4):431-8
Varutti R, Setti RF, Setti T. Headache after Delivery, a Misleading Presentation of Sheehan's Syndrome: A Case Report. Emergency Med 2019;9:389