Pregnancy is defined as the condition of having a developing embryo or foetus in the body, after the fertilisation of an ovum by a sperm. The length of a normal pregnancy varies between about 37 and 42 weeks, although the delivery (term) date is calculated at 40 weeks from the first day of the last menstrual period. Babies born before 37 weeks are considered to be premature (or preterm).

Pregnancy is traditionally divided into three stages or trimesters, each lasting about three months. Weeks 0 to 13 are known as the first trimester of pregnancy and the baby’s development is greatest during this period. Following fertilisation, the ovum immediately begins to divide into a growing cluster of cells. Between five and seven days after ovulation, the fertilised egg implants into the wall of the uterus and produces root-like outgrowths called villi. These help to anchor it to the lining of the uterus and will eventually grow into the placenta. From the time of implantation into the wall of the uterus until approximately the eighth week of life, the baby is known as an embryo. Development is rapid during this stage, as specialised cells begin to form the vital organs, nervous system, bones, muscles and blood. After eight weeks, the developing baby is called a foetus. It is about 2.4cm long, with most of the internal organs formed. External features such as the eyes, nose, mouth and ears can be seen, and fingers and toes start to appear. By the end of week 13 it will be a fully-formed foetus. Some of the common discomforts of pregnancy such as nausea, fatigue, and breast tenderness are most pronounced during the first trimester.

Weeks 14 to 26 make up the second trimester. During this stage, the foetus continues to develop and grow, and the mother may start to gain significant amounts of weight as extra fat is laid down as energy reserves. The mother may begin to feel the baby’s movements in the uterus and the baby will begin to develop patterns of activity. The placenta maintains and nourishes the baby by enabling the transfer of oxygen, carbon dioxide, amino acids, fats, vitamins and minerals from the mother’s blood. It also allows the transfer of waste substances from the growing baby.

The third trimester runs from week 27 to the birth of the baby. The baby starts to lay down its own fat stores, going through rapid growth phases in preparation for birth. The lungs mature, and senses such as hearing, taste and sight develop. Towards the end of pregnancy symptoms such as discomfort at night, backache and frequent urination are common, and practice contractions known as Braxton Hicks may occur.

There are many pregnancy-related issues that parents-to-be may wish to discuss with healthcare workers. These may include:

• conception and fertility issues
• diagnosing pregnancy
• normal foetal development
• antenatal care and education
• antenatal screening to detect abnormalities
• health during pregnancy
• maternal nutrition
• drugs in pregnancy
• complications of pregnancy
• pre-existing medical conditions (e.g. diabetes, thyroid disease, epilepsy)
• psychological issues
• multiple pregnancies
• maternal rights and benefits.

The NHS Direct on-line encyclopaedia provides a useful overview of pregnancy and provides links to sources of further information.
www.nhsdirect.nhs.uk

NHS Direct has a Frequently asked questions section concerning pregnancy and childbirth.
www.nhsdirect.nhs.uk

The Royal College of Obstetricians and Gynaecologists website has a specific ‘information for patients’ area that provides pregnancy-related information, addresses, queries and links to other useful on-line resources.
www.rcog.org.uk

Emma’s Diary is a week-by-week pregnancy guide produced by The Royal College of General Practitioners.
www.emmasdiary.co.uk

The National Childbirth Trust offers support in pregnancy, childbirth and early parenthood, and aims to give every parent the chance to make informed choices.
www.nctpregnancyandbabycare.com

Pregnancycare is a pregnancy information website for patients, students and doctors. It is provided by a Consultant and Senior Lecturer in Obstetrics and Gynaecology.
www.pregnancycare.co.uk

The WellBeing of Women charity’s website offers a useful leaflet for patients on pregnancy and labour. The leaflet gives information on preparing for pregnancy, diet, complications and antenatal tests.
www.wellbeingofwomen.org.uk

BabyCentre is a parenting resource offering practical advice from expert sources, such as obstetricians, paediatricians, doctors, midwives and parents.
www.babycentre.co.uk

The BBC website guides parents-to-be through the stages of pregnancy.
www.bbc.co.uk/parenting

Tommy’s is a charity offering information to help maximise the chance of having a healthy pregnancy. The website offers a range of publications.
http://www.tommys.org/

The 2004 Prodigy guidance on pre-conceptual counselling aims to help professionals provide the information that a woman and her partner need in order to make informed choices about planning a pregnancy and ensuring the best possible outcome. There are links to relevant patient information leaflets.
www.prodigy.nhs.uk/guidance

The 2003 Prodigy guidance on hypertension in pregnancy.
www.prodigy.nhs.uk/guidance

The 2002 Prodigy guidance on nausea and vomiting in pregnancy.
www.prodigy.nhs.uk/guidance

Prodigy guidance on iron deficiency anaemia in pregnancy and on urinary tract infections in pregnancy.
www.prodigy.nhs.uk/QuickReferenceGuides

Prodigy patient information leaflets on a range of specific aspects of pregnancy.
www.prodigy.nhs.uk/PILs

The British Nutrition Foundation offers dietary advice for pregnant women.
www.nutrition.org.uk

The Food Standards Agency provides an on-line guide to nutrition during pregnancy.
www.eatwell.gov.uk/agesandstages/pregnancy/

Government guidance on folic acid in pregnancy.
www.dh.gov.uk/PolicyAndGuidance

The British Pregnancy Advisory Service website offers information about unplanned pregnancy.
www.bpas.org.uk

Obstetric Ultrasound is an educational website covering all aspects of ultrasound during pregnancy.
www.ob-ultrasound.net

The Miscarriage Association website provides information for people who experience pregnancy loss.
www.miscarriageassociation.org.uk

The Multiple Births Foundation (MBF) and the Twins and Multiple Births Association (TAMBA) have websites providing information about multiple pregnancies for parents-to-be and for health professionals.
www.multiplebirths.org.uk        www.tamba.org.uk 

The Contact a Family charity provides background information about genetics and specific medical conditions, including inherited disorders.
www.cafamily.org.uk

Adviceguide is the on-line Citizen Advice Bureau (CAB) service that gives information about benefits and rights in pregnancy in all four UK countries.
www.adviceguide.org.uk

The Maternity Alliance is a national charity working to improve rights and services for pregnant women, new parents and their families.
www.maternityalliance.org.uk

The Women's Health specialist library is a virtual library providing access to a growing collection of quality evaluated resources and links for health professionals working in the fields of obstetrics and gynaecology, and also for patients and others interested in the topics. Provided by the National Library for Health (NLH), this on-line library provides access to information on a wide variety of topics concerning women's health issues and links to relevant National Institute for Clinical Excellence (NICE) guidelines on fertility and Caesarean section and to journals, textbooks and professional organisations.
www.library.nhs.uk/womenshealth

The World Health Organization (WHO) Pregnancy page offers links to activities, reports, events and news relating to pregnancy issues.
www.who.int/topics/pregnancy

The National Institute of Clinical Excellence (NICE) clinical guidelines for pregnancy and labour.
www.nice.org.uk

The Royal College of Midwives is Britain’s professional union of midwives. Its Information Centre provides information and advice on a wide range of midwifery and antenatal issues.
www.rcm.org.uk

The British Journal of Midwifery archive.
www.intermid.co.uk

The British Medical Journal Publishing Group’s Clinical Evidence website is a source of the best available evidence for effective healthcare during pregnancy.
www.clinicalevidence.com

The British Medical Journal provides a collection of articles on pregnancy and childbirth published in the journal since January 1998 (usually with links to the full-text) bmj.bmjjournals.com/pregnancy and a collection of articles on drugs in obstetrics bmj.bmjjournals.com/obsdrugs

BMC Pregnancy and Childbirth is an open access, peer-reviewed journal that considers articles on all aspects of pregnancy and childbirth.
www.biomedcentral.com/bmcpregnancychildbirth

GP notebook is a system designed to provide a concise synopsis of the entire field of clinical medicine with material organised systematically to ensure rapid retrieval of information. The Obstetrics section covers various aspects of pre- and peri-natal care.
www.gpnotebook.co.uk

NMAP offers free access to a searchable catalogue of hand-selected and evaluated, quality internet resources for nursing, midwifery and allied health professions.
nmap.ac.uk

Midwives online is a web-based portal dedicated to the information needs of midwives in the UK and globally. It aims to link to quality, relevant, timely and where appropriate, evidence-based information to support midwives. There is also a section for parents-to-be.
www.midwivesonline.com