Select a condition Absence seizures Acne ADHD Age-related macular degeneration AIDS Alzheimer's disease AMD Amebic dysentery Anal tears Angina, stable Angina, unstable Ankle sprain Anorexia Anxiety Appendicitis Arthritis Asthma in adults Asthma in children Athlete's foot Atrial fibrillation Attention deficit hyperactivity disorder (ADHD) Autism Back pain Bacterial vaginosis Bad breath Bedsores Bedwetting Bell's palsy Benign prostatic hyperplasia Bipolar disorder Bladder infection in women Blood pressure Breast cancer Breast pain Bronchiectasis Bronchiolitis Bronchitis Bulimia Bunions Burning mouth syndrome Burns and scalds Canker sores Cardiac arrest Carpal tunnel syndrome Cataracts Cellulitis and erysipelas Chickenpox Childbirth, heavy bleeding Childbirth, tear or cut Chlamydia Chronic bronchitis Chronic fatigue syndrome Chronic obstructive pulmonary disease Chronic prostatitis Chronic tension type headache Cold sores Colic in babies Colon and rectal cancer Colon and rectal cancer screening Colonic diverticular disease Common cold Conjunctivitis Constipation in adults Constipation in children COPD Crib death Deep vein thrombosis Dementia Depression in adults Depression in children Diabetes, type 1 Diabetes, type 2 Diarrhea in adults Diarrhea in children Diverticular disease Ear infection, middle ear Ear infection, outer ear Ear infection with discharge Ear infection with fluid Ear pain during air travel Ear wax Eczema Emphysema Endometriosis Enlarged prostate Epilepsy Episiotomy Erection problems Essential tremor Febrile seizures Fertility problems Fibroids Flu Gallstones Genital herpes Genital warts GERD GERD in children Glaucoma Gonorrhea Gout Group B streptococcus H. pylori infection Halitosis Hay fever Headache, chronic tension type Head lice Heart and circulation problems in diabetes Heart attack Heartburn Heart failure Heavy periods Heel pain Hemorrhoids Hepatitis B Hepatitis C Hernia Herpes, genital Herpes simplex eye infection High blood pressure High blood pressure in pregnancy High cholesterol HIV infection Hyperactivity IBS Incontinence in women Infection in newborn babies Infertility Influenza Insomnia in adults Irritable bowel syndrome Jaundice in newborn babies Jet lag Kidney infection Kidney stones Leg cramps Leg ulcers Lewy body dementia Lung cancer Lyme disease Macular degeneration Malaria prevention Manic depression Mastalgia Measles, mumps and rubella: prevention Melanoma Meniere's disease Meningococcal disease Menopause Migraine in adults Migraine in children MMR prevention Morning sickness Multiple sclerosis Nail infection, fungal Neck pain Nicotine addiction Non-Hodgkin's lymphoma Nosebleeds in children Obesity Obsessive-compulsive disorder OCD Oral thrush Osteoarthritis Osteoporosis Ovarian cancer Painful periods Pancreas cancer Panic attacks Parkinson's disease PCOS Pelvic inflammatory disease Perineal care Peripheral arterial disease Peripheral vascular disease Pneumonia Polycystic ovary syndrome Postpartum depression Postpartum hemorrhage Post-traumatic stress disorder Preeclampsia Pregnancy, nausea Premature birth Pressure sores Prostate cancer Prostatitis, chronic Psoriasis PTSD Raynaud's disease Rectal cancer screening Recurrent cystitis Reflux in children Rheumatoid arthritis Scabies Schizophrenia Seasonal allergy Shoulder pain Sickle cell anemia Sickle cell disease SIDS Sinusitis Skin cancer (melanoma) Skin cancer (squamous cell) Sleep apnea Sleep problems in children Slipped disk Smoking Sore throat Stomach ulcers Stress headache Stress incontinence Stroke, emergency care Stroke prevention Sudden infant death syndrome Swimmer's ear Tennis elbow Tension headache Testicular cancer Thrush (oral) Tic douloureux Tinnitus Tonsillitis Toxoplasmosis in pregnancy Trigeminal neuralgia Underactive thyroid Urinary tract infections in children Varicocele Varicose veins Vascular dementia Warts Whiplash Wisdom teeth, impacted Wrinkles Yeast infection, vagina

Select treatment area Bladder & Kidneys Blood Brain & nervous system Cancer Children's health Diabetes Digestive system Ear, nose & throat Eating & weight Eyes Fertility Heart and circulation Hormones Infections Lungs & breathing Men's health Mental health Mouth Muscles & bones Pregnancy & childbirth Sexual health Skin Sleep Staying healthy Travel health Women's health

No one knows for sure why some women get nausea and vomiting when they are pregnant and others do not. But there are certain things that can increase your chances of getting morning sickness when you're pregnant. Doctors call these risk factors.

If you have one of the following risk factors, keep in mind that this doesn't mean that you will definitely get nausea and vomiting or get it very bad. It just means your chances of getting it are somewhat higher.

• If you're having twins, you're more likely to feel sick to your stomach and throw up than if you're carrying one baby.¹
• When the organ that normally carries food and oxygen to a growing baby (called the placenta) grows abnormally, it's called a hydatidiform mole or molar pregnancy.¹ Women who have molar pregnancies often have severe nausea and vomiting.
• If you had nausea and vomiting during an earlier pregnancy, it's more likely that you'll have it during other pregnancies.²
• If your mother had very bad nausea and vomiting when she was pregnant, some research shows that you may, too.^{2 3 4}
• If you have felt sick to your stomach while using birth-control pills,³ you may have a greater chance of morning sickness during pregnancy.
• If you get motion sickness or migraine headaches, there's some evidence that you are more likely to have severe nausea and vomiting when you're pregnant.⁵ Doctors believe these problems have something to do with your inner ear, which helps control your balance.⁶ But we don't yet know whether treating inner ear problems will help prevent nausea and vomiting during pregnancy.
• A germ called Helicobacter pylori can cause stomach problems such as indigestion and ulcers. For some women, this might make nausea and vomiting worse. One study found that women who vomited a lot in pregnancy were more likely to be infected with Helicobacter pylori than women who didn't. ⁷ Some treatments can get rid of the germ, but they probably won't be used when you're pregnant. You may be able to take some medication to help reduce your symptoms, such as antacids. But you should talk with your doctor before taking any medication during pregnancy.
• One study has found that eating foods that contain a lot of saturated fat, such as meat, cheese and butter, may increase your chances of having bad nausea and vomiting during pregnancy.⁸ But the study was small, so we need more research before we can say whether eating low-fat foods can help.
• Nonsmokers may have more nausea than smokers, but doctors do not encourage you to smoke. Smoking when you're pregnant harms your baby.²
• Some studies show you are more likely to feel sick to your stomach during pregnancy if you are expecting a girl.³ But other studies have found no link to the sex of the baby.⁴

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment. ©BMJ Publishing Group Limited 2008. All rights reserved.