The modern obstetrician and gynaecologist is increasingly using a wide range of equipment and instruments in their clinical practice, for both diagnostic and therapeutic purposes. With the introduction of the new curriculum, a basic understanding and use of ultrasound imaging are mandatory for all, in addition to a knowledge of conventional diagnostic and therapeutic techniques. However, not all practitioners fully appreciate the background principles on which these techniques are based. It is not so much the complex knowledge of physics and formulae that is required, but rather a knowledge of how the principles of physics are applied in clinical practice. This is fundamental to a better understanding of the techniques as well as their safe, optimal and efficient use. This chapter will consider the scientific foundations and uses of a procedure frequently encountered in obstetric and gynaecological practice.

lysozyme-tissue fluids (tears, sweat, urine; not CSF) and in cytoplasmic granules of polymorphic neutrophils. Split polysaccharides of bacterial cell walls

Put in the broadest terms, the events taking place during the first four weeks of development following fertilisation lay the foundations for the development of the structures of the body (i.e. organ systems). Early embryonic development encompasses some key developmental events and processes that result in the production of sufficient cells, of the right type in the right place to ensure that structural development of the organs can proceed. These events and processes are linked and inter-dependent and can be conceptualised as a cascade of events where a given event primes the succeeding event.

As in ‘Data Interpretation in Obstetrics,’ questions can draw on knowledge from the entire Part 1 curriculum. As the new Part 1 exam including the clinical domains is now well established, themes of questions over the past three years have been examined and represented as follows.

Fats have energy-storing, structural and regulatory roles in the body (Table 25.1). Depots of white adipose tissue (WAT) therefore not only function to store energy but also to provide precursors for synthesis of other species. Specific roles are played by certain fatty acids in this regard. For example, long-chain derivatives of the essential fatty acids of the omega 3 series (which cannot be synthesised de novo but must be taken in through the diet and modified) contribute to membrane formation in the CNS and the retina. The importance of the roles played by omega 3 fatty acids in anchoring specific membrane proteins involved in signalling is illustrated by the effects of dietary deficiencies. About ⅔ of the total content of docosahexaenoic acid (22 carbon fatty acid derived from linolenic acid) are assimilated in the final three months of gestation and the remaining ⅓ during the first three months of life. An interruption of supply during these crucial periods produces a measurable adverse effect on the development of cognitive function and of visual acuity.

The pelvic girdle is inclined, forwards, such that, in the anatomical position, the pubic tubercle and the anterior superior iliac spine (ASIS) lie in the same vertical plane and the pubic symphysis and ischial spine lie in the same horizontal plane.

The primitive gut tube arises as a consequence of folding of the embryo, a process which is complete by the end of the fourth week after fertilisation. The primitive gut tube is formed as an endoderm lined tube with blind diverticula at the cranial and caudal extremities. These blind-ending diverticula are bounded from the exterior by the buccopharyngeal and cloacal membranes at the cranial and caudal ends, respectively. At its formation, and critical to development of the gastrointestinal (GI) tract, the primitive gut tube maintains continuity with the yolk sac from which it is formed via the vitelline duct at the umbilicus.

The lung volumes in a non-pregnant normal individual are shown in Fig. 1.3. These include the tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), residual volume (RV), total lung capacity (TLC), vital capacity (VC) and functional residual capacity (FRC).

A surgical site infection (SSI) is a healthcare-associated infection occurring after an invasive or surgical procedure. It is usually localized to the incision site but can extend into deeper structures with presentation delayed up to 30 days. SSI accounts for up to 20% of all healthcare-associated infections [2].

The establishment of genito-urinary medicine (GUM) clinics, and latterly sexual and reproductive health clinics, was designed to treat and deal with the complications of STIs and related genital conditions in a permissive and confidential environment. Confidentiality is paramount in sexual health, and clinical information is not routinely shared with other healthcare providers, unless it facilitates care, and then only with the express permission of the patient. Information is held separately from the general medical record and patients may register with partial or alternate demographic details. Services are delivered by a multidisciplinary team comprising doctors, nurses (often in advanced practitioner roles), health advisors, healthcare assistants and laboratory staff.

Before birth, the pulmonary circulation is at high resistance owing to compression of the capillaries by collapsed lung and the vasoactive effects of the low PO2. Conversely, systemic circulation is at low resistance owing to the large placental bed. These factors, along with the presence of shunts, allow blood to be diverted from the lungs to the placenta.

It occupies the bony space within the skull called Sella turcica.

The normal cell maintains a steady state, termed homeostasis, in which the internal milieu of the cell is kept within physiological parameters. The response of a cell to any change in its environment constitutes the pathophysiological basis of clinical symptoms. When cells are faced with physiological or pathological stress they respond in several ways, collectively known as cellular adaptation. When the capacity of the cell to adapt is exceeded, then the cell undergoes a series of changes referred to as cell injury. The degree of injury dictates whether the cell will recover (i.e. reversible cell injury) or progress to cell death (i.e. irreversible cell injury). The effect on the tissue will depend on the duration of the injury, the nature of the injurious agent, the proportion and types of cells affected and the ability of the tissue to regenerate.

Statistics is often cited as one of the more difficult topics examined in the Part 1 MRCOG. Some candidates avoid the subject and hope to compensate by higher scoring in other subjects. This is unwise as the statistical component of the examination is significant and is also an easy way to gain substantial marks. While writing questions for the Part I examination and running Part I courses, it became obvious that the types of statistical questions asked were very limited with a repetitive nature (though, of course, the numbers are changed). This synoptic chapter will give you the appropriate level of knowledge of statistics required for the Part I examination.

Despite both being derived from lipid substrates, steroid hormones and prostaglandins differ fundamentally in their molecular structures, biosynthetic pathways, mechanisms and speed of action. This chapter covers each of these topics in turn, comparing and contrasting the synthesis and actions of steroids versus prostaglandins. In the final section, the functional interactions between these two families of lipid hormones are considered in the physiological control of myometrial contraction at parturition.

Human pregnancy is characterized by haemomonochorial placentation (where only a single layer of trophoblast tissue separates the mother’s and fetal blood), with earlier and deeper invasion into the maternal decidua and myometrium than in any other mammalian species.

Evidence-based medicine (EBM) is a process that allows the optimization of decisions in medicine through the analysis and application of evidence from research.

The graphical representation of meta-analysis of multiple randomized controlled trials.

This chapter starts with rationale, counselling regarding potential benefits and risks and inclusion and exclusion criteria for spina bifida surgery before birth. Pre-operative assessment is outlined and technical aspects are illustrated and described.

This chapter covers indications, technical aspects and pre- and post-procedure management for laser fetoscopy, radiofrequency ablation, bipolar coagulation, interstitial laser, fetoscopy for twin–twin transfusion syndrome and various interventions for selective growth restriction and twin anaemia polycythaemia sequence. The chapter also includes description of tracheal occlusion (FET), intervention for chorioangioma and fetal cystoscopy.