A mother who had the same condition as the Duchess of Cambridge says the illness is debilitating.
Sara Hannak from Belper suffered from hyperemesis gravidarum during her first and second pregnancy.
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Duller conditions moving back towards the coast through the morning, leaving a mainly dry day with warm sunny spells.
Showery outbreaks of rain will become more widespread through Thursday with heavy and locally thundery downpours possible.
Pollen: West Midlands Update