10 November 2022 |

Magnesium in pregnancy: an important role in uterine contractions and blood pressure

magnesio in gravidanza - donna con il pancione seduta a gambe incrociate

Pregnancy is a very delicate time in physiological terms: the body undergoes huge changes, and this is why it is important to pay attention to general physical and mental well-being and nutrition. To stay in good health during the 9 months of pregnancy and ensure the correct development of the foetus, future mothers often focus on their diet, but this may not be sufficient to ensure the correct intake of essential nutrients. Mineral and vitamin requirements in pregnancy increase and the use of supplements (always according to the advice of the gynaecologist) is very common.

Minerals in pregnancy: the fundamental nutrients

The fundamental minerals during pregnancy include:

  • Calcium: this promotes the correct mineralization of the foetus’s bones and teeth (yes, your baby develops teeth in the uterus!) and prevents a reduction in bone density in mothers.
  • Iodine: an essential mineral for foetal growth and development, as well as for the mother’s health, especially in the first quarter when the future mother’s thyroid increases its activity in order to synthesise the thyroid hormones for the baby too: the World Health Organisation (WHO) recommends a daily intake of 250 mcg.
  • Iron: iron requirements increase considerably during pregnancy (in fact to almost twice that of the normal conditions of a non-pregnant woman), especially in the last quarter, as it has to meet not only the mother’s body needs but also the development of the foetus.
  • Zinc: is a mineral needed for the activity of over 300 enzymes and is essential for the life and growth of the foetus as it is involved in cell reproduction, supporting the development of bones, muscles, sexual organs and the thyroid.
  • Magnesium: during pregnancy magnesium is useful particularly for women’s health, as it helps to prevent hypertension (high blood pressure), uterine contractions and the onset of back pain, due to its relaxing effect on the smooth muscles. Let’s see how it acts on contractions and blood pressure control mechanisms.

The role of magnesium in pregnancy

Magnesium is a macroelement, in the body quantities vary from 22 to 26 g, of which more than 50% is found mineralised in the bones. Magnesium is a co-factor for more than 300 enzymes and is therefore involved in a great number of processes, from the synthesis of neurotransmitters essential in our central nervous system, to the production and release of cell energy. What’s more, as magnesium acts in balance with calcium, it also contributes to the control of fundamental processes such as muscular contractions, heart beat, coagulation and blood pressure.

The daily requirement of magnesium can vary according to physical characteristics, but is generally between 280 and 400 mg. For women in pregnancy, the minimum requirement of magnesium is 320 mg a day.

Thanks to its muscle function, during pregnancy this mineral is important for controlling muscle contractions, and consequently helps to keep the uterus relaxed. Magnesium deficiency in pregnancy is a risk factor for early uterine contractions, which could lead to premature birth. Furthermore, guaranteeing all the magnesium the body needs helps to prevent and combat some typical problems during pregnancy such as insomnia, irritability and asthenia. Finally, magnesium helps to control blood pressure values, intervening in the carbohydrate metabolism; it is therefore important for protecting cardiovascular health in pregnant women as well as the correct development of the foetus.

Magnesium and uterine contractions

Uterine contractions are simply involuntary movements of the uterine muscles that occur during pregnancy and childbirth. They can often be felt during the nine months of pregnancy: each contraction has a function, and it is important to be able to distinguish them in order to avoid pointless worry.

At the start of pregnancy, the uterus contracts occasionally in a physiological manner: this is a sign that it is adjusting to the presence of the foetus and is preparing to gradually increase in size. There is no need to worry about this type of contraction, and indeed many women do not even feel them.

During the second quarter uterine contractions can be felt more clearly, even if they are no painful: the tummy suddenly hardens due to swelling of the uterus or foetal movements. Physical tiredness also greatly affects this type of contractions, which are a sign to the body that it should stop and rest. This is why many gynaecologists recommend a daily supplement of magnesium and mineral salts, which help to control muscle activity and, consequently, keep the uterus relaxed.

The correlation between uterine contractions and magnesium deficiency is very subtle. Intense and frequent contractions, especially into the third quarter, could lead to the risk of premature childbirth, the incidence of which is 10% more in the case of in advanced magnesium deficiency.

Hypertension during pregnancy

Hypertension in pregnancy is one of the main causes of maternal and perinatal mortality worldwide. Preeclampsia, or gestosis, is a rather frequent condition in the last six months of pregnancy, characterised by an increase in blood pressure (over 90 mmHg minimum and 140 mmHg maximum) and the excretion of proteins in the urine (over 300 milligrams a day). It has been estimated that preeclampsia affects 2-8% of pregnancies globally.

Let’s clarify a fundamental issue: magnesium, when taken in the recommended doses through a balanced diet or, if necessary, with specific supplements, helps to reduce the risk of hypertension during pregnancy, but is not a preventive cure or a treatment for women suffering from gestosis, who must be closely monitored by a doctor for the intake of specific drugs.


The recommendations for pregnant women are to focus on a well-balanced diet with important sources of specific nutrients. Supplements can help some people who avoid certain food groups such as meat or animal products, or who are at greater risk of deficiencies.

In cases of magnesium deficiency in pregnancy, UltraMag® can help to guarantee the appropriate daily intake of the mineral as a dietary supplement.

UltraMag® is a food supplement with magnesium oxide, which uses Sucrosomial® Technology: Here the mineral is conveyed in a matrix of phospholipids and sucrose esters of fatty acids, which enables high absorption of magnesium and optimal gastrointestinal tolerability. The daily dose of magnesium in UltraMag® is 375 mg, corresponding to 100% of the Nutrient Reference Value (NRV). For this reason we recommend taking one sachet a day dissolved in a glass of water, at any time of the day.



  • Brown, C. Wright. Safety and efficacy of supplements in pregnancy. Nutr Rev. 2020 Oct 1;78(10):813-826. doi: 10.1093/nutrit/nuz101.
  • Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin Summary, Number 222. Obstet Gynecol. 2020 Jun;135(6): 1492-1495.doi: 10.1097/AOG.0000000000003892.
  • Euser A.G., et al.; Magnesium sulfate for the treatment of eclampsia: a brief review. 2009 Apr;40(4):1169-75.

gravidanza integratori magnesio minerali