Definition: There is no established definition for what constitutes reduced fetal movements (RFM), but the RCOG considers less than 10 movements within 2 hours (in pregnancies past 28 weeks gestation) an indication for further assessment.

[Fetal movements should be established by 24 weeks gestation]

Reduced fetal movements can represent fetal distress, as a method of fetal compensation to reduce oxygen consumption as a response to chronic hypoxia in utero. This is concerning, as it reflects risk of stillbirth and fetal growth restriction. It is believed that there may also be a link between reduced fetal movements and placental insufficiency.

Epidemiology: Reduced fetal movements is a fairly common presentation, affecting up to 15% of pregnancies. 3-5% of pregnant women will have recurrent presentations with RFM.

Physiology

The first onset of recognised fetal movements is known as quickening - 18-20 weeks gestation, increase until 32 weeks then plateus

Multiparous women will usually experience fetal movements sooner, from 16-18 weeks gestation. Towards the end of pregnancy, fetal movements should not reduce.

Risk factors

• Posture
  • There can be positional changes in fetal movement awareness, generally being more prominent during lying down and less when sitting and standing
• Distraction
  • Awareness of fetal movements can be distractable, and if a woman is busy or concentrating on something else, these can be less prominent
• Placental position
  • Patient with anterior placentas prior to 28 weeks gestation may have lesser awareness of fetal movements
• Medication
  • Both alcohol and sedative medications like opiates or benzodiazepines can temporarily cause reduced fetal movements
• Fetal position
  • Anterior fetal position means movements are less noticeable
• Body habitus
  • Obese patients are less likely to feel prominent fetal movements
• Amniotic fluid volume
  • Both oligohydramnios and polyhydramnios can cause reduction in fetal movements
• Fetal size
  • Up to 29% of women presenting with RFM have a SGA fetus

Investigations