Midwifery

The Basics

Helen Baston

• Publisher: Routledge
• Year: 2020
• eBook ISBN: 9780429627361
• Edition: 1
• Topic: Medicine
• Subtopic: Gynecology, Obstetrics & Midwifery

Midwifery: The Basics provides an engaging and authentic insight into the midwife's world. It explores the role of the midwife as a clinician and professional, showing how midwives can support women both to achieve a healthy full-term pregnancy and a smooth transition to motherhood.

This book begins with a discussion of the context of birth and parenthood, placing midwifery in its broader social context. Topics covered include:

• the midwife as an autonomous professional;
• becoming a midwife;
• pre-conceptual and antenatal care;
• intrapartum care;
• postnatal care; and
• the specialist midwife.

Midwifery: The Basics uses the voices of mothers, fathers and midwives to illustrate the complex world of becoming, being and supporting parents. This is an essential introduction for students at undergraduate and A-Level who are approaching midwifery for the first time.

The context of birth

Introduction

Each woman is unique and brings with her a background of influential health and social factors that will play a significant role in her expectations and experiences of pregnancy, birth and motherhood.

This chapter is about the social, epidemiological and emotional context of having a baby and becoming a parent to provide a backdrop for subsequent chapters which focus on midwifery and maternity care delivery. We need to understand what it means to become a mother, what impacts on women’s experiences and how that appraisal might be enhanced by the care midwives give.

Before we explore the wider context of birth we must first understand the basis of all human needs – safety. There will be no context if there is no survival. Crucial to survival during childbirth is an understanding of how new life is formed and develops, how the mother’s body adapts during pregnancy to protect and grow her baby. Then, through the extraordinary process of labour and birth, the baby emerges into the outside world and the mother’s body makes its rapid return to its pre-pregnancy state, so it can continue its reproductive function. Her body also prepares to nurture her baby through the initiation of lactation, a process during which the mother–infant dyad is reunited.

Maslow’s hierarchy of needs (1943) provides a useful model for thinking about the context of birth; it illustrates that as humans we first have basic physiological needs which need to be addressed above all others. Then we need to be safe; have nourishment, good health and a place to live. Love and belonging come next illustrating our need to make connections with people; family, friends and community. Only when these requirements are in place can we develop self-esteem, feeling good about ourselves and being recognised as individuals with respect and dignity by others. The cherry on the cake is reaching self-actualisation; becoming the most that we can be. This linear model does not of course capture what is now better understood, that our social connections and well-being can impact on our physical health (Holt-Lunstad et al. 2017), but that’s another story.

Physiology

Conception and fetal development

Each month of the menstrual cycle an egg is released from the ovary into the fallopian tube. Following sexual intercourse, sperm migrate from the vagina, through the cervix into the uterus and swim up the fallopian tubes. When one sperm penetrates the egg, the gametes unite, and the egg is fertilised and becomes a solid ball of rapidly dividing cells (morula) and continues down the fallopian tube into the uterus where it embeds. It is called a blastocyst when it becomes a hollow ball of cells which is one-cell thick, except in one area which is thicker. The cells nearest the lumen of the blastocyst become the embryo and those nearer the outer wall, the trophoblast, become the placenta. The trophoblast further differentiates into an outer membrane known as the chorion, which surrounds the blastocyst, and an inner membrane known as the amnion, which develops into the amniotic sac. The sac begins to fill with amniotic fluid which the developing embryo floats in. The developing placenta starts to produce a hormone called human chorionic gonadotrophin (hCG) which acts on the ovaries preventing further ovulation and stimulating the production of oestrogen and progesterone and maintenance of the corpus luteum. Oestrogen and progesterone are also produced from the developing placenta and levels are adequate by 5–6 weeks, from which time production from the corpus decreases.

The organs begin to form by three weeks and with the exception of the spinal cord and brain, are completely formed by 10 weeks conceptual age. Eight weeks after fertilisation the embryo is called fetus until birth. Fetal development is incredibly rapid. By 16 weeks of pregnancy the fetus can hear, swallow, make urine and flex its arms and legs. By 20 weeks it can suck, sleep and wake, has fingernails and in female fetuses its ovaries contain eggs. By 24 weeks it has tear ducts and fingerprints and by 28 weeks it can respond to sound and open and close its eyes (ACOG 2018).

Preterm birth

Babies born before 37 completed weeks of pregnancy are defined as ‘preterm’; however, many babies are born much earlier than that. Advances in nursing and medical technologies mean that many more babies are surviving than would have previously, although some are likely to have long-term health challenges or significant disability. In the UK, 10 per cent of babies survive from 22-week gestation; 60 per cent at 24 weeks; 89 per cent at 27 weeks; 95 per cent at 31 weeks; and after 34 weeks this is equivalent to full term (Tommy’s 2019).

Pregnancy

During pregnancy the female body undergoes significant changes to many organs and systems.

Progesterone, responsible for the development of the lining of the womb in preparation for implantation, continues to exert a role in preventing rejection of the embryo by suppressing contractions of the uterus. This function is taken over by the placenta and levels increase throughout pregnancy. Progesterone is responsible for breast tenderness and nausea in pregnancy, often experienced as early signs of pregnancy. It is also responsible for the growth of the uterus from its non-pregnant pear size to being able to carry a fully grown fetus. By 12 weeks of pregnancy the uterus can be palpated above the symphysis pubis, at the umbilicus at 20–22 weeks and just under the xiphisternum at 36 weeks (see Chapter 5).

Gastrointestinal changes

Many women experience nausea and vomiting in early pregnancy although for some it can persist throughout. In rare circumstances it can be debilitating (hyperemesis) and require intravenous fluid replacement to correct the subsequent electrolyte imbalance. It can also be associated with increased salivation (ptyalism). The gums can become swollen and bleed more readily in pregnancy. Some women experience cravings for non-foods during pregnancy, which is known as pica, but it is not known to be harmful. Oestrogen causes the appetite to be suppressed; however, progesterone stimulates it and thirst is increased; the shift in balance leads to an increased appetite in about 50 per cent of women (Coad 2011). Women often find their dietary intake increases, but there is no additional need for calories until the third trimester, and then only 300 kcal per day (NICE 2008a).

Progesterone’s impact on smooth muscle tone means that the tone of the oesophageal sphincter is relaxed and acid from the stomach causes an unpleasant burning sensation or heartburn. The intestine and colon also become more relaxed and motility is reduced, leading to an increased risk of constipation.

Cardiovascular changes

During early pregnancy the blood pressure falls slightly, which can lead some women to feel faint. Then the blood volume starts to increase by as much as 30–50 per cent, which is accommodated by an increased number of blood vessels, stimulated by oestrogen, and relaxation of the smooth muscle of the vessel wall, caused by progesterone. The overall impact on the cardiovascular system gives rise to an increased cardiac output, as a result of increased heart rate and stroke volume of the slightly enlarged heart. Blood pressure (diastolic) is lower in the first two-thirds of pregnancy and returns to its pre-pregnancy value by the end of pregnancy.

It is usual for most women to experience some swelling (oedema) in their hands, feet and ankles due to the effects of reduced venous return because of the space occupied by the uterus and the increased laxity of the blood vessels. The increased blood volume is not accompanied by a corresponding increase in plasma protein or red cells hence fluid is more likely to leak from the capillaries into the tissues. Elevation of the legs while sitting can help reduce the swelling, as can moderate exercise, such as brisk walking and swimming (PHE 2019a).

The blood red cell mass only increases by up to 20 per cent, from about 12 weeks of pregnancy. To meet the requirements for iron in pregnancy, the woman needs to have good iron stores pre-conceptually, despite increased iron absorption during pregnancy. Routine supplementation with iron is therefore recommended in countries where the diet of the population is poor (WHO 2017a); it is not currently recommended in the UK (NICE 2008b).

Pregnancy is a time when the risk of thrombosis is increased because there is venous stasis, increased fibrin and reduced fibrinolytic activity and endothelial damage (Devis & Knuttinen 2017). It is thought that this is an evolutionary development to protect women from haemorrhage during the birth. However, thrombosis is the leading cause of maternal death in England (Knight et al. 2018); a risk that increases with maternal age and body mass index.

Renal changes

The anatomy of the kidneys changes during pregnancy because of the impact of progesterone, which causes the ureters to lose tone and become elongated. Urinary stasis is increased and can lead to urinary tract infection (UTI). There is increased glomerular filtration and tubular reabsorption, leading to increased sodium and subsequent fluid retention. The bladder is under pressure from the growing uterus in the first trimester, until the uterus becomes an abdominal organ, leading to increased frequency of micturition. When the fetal head (96 per cent of babies present head-first at term) starts to engage in the pelvis towards the end of pregnancy, these symptoms return.

Respiratory changes

To increase the efficiency of gaseous exchange tidal volume increases and alveolar ventilation increases due to the relaxation of smooth muscle in the bronchioles. Also, the softening of cartilage and muscle in the thorax facilitates chest expansion. Some women become breathless in pregnancy and anaemia or heart anomaly should be ruled out before this is attributed to reduced space below the diaphragm. Oedema of the vocal cords can lead to a deepening of the voice.

Skeletal changes

Due to the impact of the hormones progesterone and relaxin on the joints, the symphysis pubis can become more mobile and even separate. The sacroiliac joints in the pelvis also become more flexible to increase the pelvic outlet for birth. Combined with the above and the increased weight of the gravid uterus and breasts, pregnant women can appear to waddle and arch their backs when they walk.

Labour and birth

The mystique of pregnancy and childbirth continues as we still have a lot to learn about the complex interplay of the factors which lead to the onset of spontaneous labour. Whilst it is thought that fetal factors have a role to play when labour starts, the mechanisms are unclear.

The cervix is the gatekeeper, holding the fetus in the uterus. For the baby to be born, the cervix needs to become fully dilated to enable the baby to pass from the uterus, through the vagina and to the outside world. In obstetric terms the dilatation of the cervix is measured from closed (0 cm) to fully open (10 cm) and this is usually assessed by regular vaginal examinations. During pregnancy, the cervix of the primigravid woman is closed and has thickness, somewhat like a doughnut with a closed hole in shape. Towards the end of pregnancy, the woman will experience ‘Braxton-Hicks’ contractions, which are usually painless uterine contractions. These herald the beginning of the long process of softening and preparing the cervix for dilatation, but they may be experienced for several weeks before labour starts.

Latent phase

This is the pre-labour phase, which is variable between individuals. It can start with what are experienced as regular, painful contractions which may last a few hours and then fade away. Other women experience mild, irregular contractions before getting into a more established pattern. During this time the cervix begins to soften and dilate up to 4 cm.

During the latent phase and with uterine contractions the length of the cervix shortens, which is known as ‘effacement’. The uterus and the cervix are continuous with each other. As the cervix effaces and softens its thickness becomes taken up into the body of the uterus, from the external cervical os upwards. In women who have previously given birth, effacement and dilatation can occur simultaneously.

Due to the unique property of the myometrial muscle fibres, following contraction, they become shorter and retract. The top (fundus) of the uterus becomes thicker and during a contraction, pressure is exerted in line with the long axis of the baby. The lower segment of the uterus thins and accommodates the head of the baby as it descends. Pressure of a well-fitting fetal head on the cervix gives rise to the release of local prostaglandins, which in turn stimulates the release of oxytocin which causes the uterus to contract. Uterine contractions in turn assist with the application of the pressure of the presenting part on the cervix and so this cycle is self-perpetuating. However, if the head is not fitting well, perhaps because the baby is in an awkward position or a full bladder or bowel are causing the head to be high in the pelvis, then uterine contractions will be less efficient. Whilst the bag of waters surrounding the baby remain intact, they form forewaters in front of the baby’s head which enables the pressure to be distributed evenly over the cervix. This bag of amniotic fluid can ‘break’ at any time, before or during any stage of labour, and whilst often portrayed in the media as a dramatic gush leaving the woman standing in a puddle, it is often a much more subtle leak.

First stage of labour

During this active stage of labour, dilation of the cervix, from 4 to 10 cm, begins to accelerate at a rate of approximately 1–2 cm per h...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• List of figures
• Preface
• Note
• Acknowledgements
• 1. The context of birth
• 2. The roles of the midwife
• 3. Midwifery – an evolutionary tale
• 4. Becoming a midwife – a leap of faith
• 5. Pre-conceptual and antenatal care
• 6. Labour and birth care
• 7. Postnatal care
• 8. Midwife as specialist
• Glossary
• Appendix 1: The PINK study (Baston 2006)
• Index