O



O




obesity in pregnancy excessive fat storage throughout body; increase in weight beyond norm in relation to gender, age, height and bone structure. May cause menstrual and fertility problems. Pregnancy complications include hypertension, gestational diabetes, urinary tract infection, difficulty with determining fetal position, large for gestational age baby, Caesarean section, poor wound healing, postpartum haemorrhage, thrombophlebitis; obesity is significant risk factor for maternal death. Classifications of obesity relate to body mass index (bmi): 30.0–34.9 (Class I); BMI 35.0–39.9 (Class 2); BMI 40 and over (Class 3 or morbid obesity), Morbid o. refers to those who are more than 50% above ideal body weight.


oblique slanting. See pelvis. O. lie abnormal lie in which long axis of fetus lies between oblique diameters of pelvis; may progress to shoulder presentation and obstructed labour with risk of cord or arm prolapse, ruptured uterus, haemorrhage and fetal or even maternal death.


oblongata See medulla oblongata.


observational study epidemiological study of events without intervention of investigator.


obsessive compulsive disorder (OCD) psychiatric anxiety disorder characterised by obsessive thoughts and compulsive actions, e.g. cleaning, checking, counting, hoarding; may occur postnatally as hormones fluctuate, or may pre-exist, leading to relapses during and after pregnancy.


obstetric pertaining to obstetrics. O. cholestasis See intrahepatic cholestasis of pregnancy. O. conjugate pelvic diameter from sacral promontory to upper inner border or symphysis pubis, measuring approximately 11 cm; first narrow strait through which fetal head has to pass. O. history detailed information about all previous pregnancies, including abortions, labours, puerperia and babies, recorded when woman books with midwife or doctor for subsequent pregnancy. O. pulsar appliance used for transcutaneous electrical nerve stimulation. O. shock collapse associated with childbirth caused by circulatory failure, occurring most commonly due to haemorrhage or trauma, e.g. acute uterine inversion, or septicaemia caused by Gram-negative organisms.


obstetrician doctor specialising in care of women with abnormal pregnancies, labours and puerperia. See also midwife.


obstetrics branch of medicine dealing with pregnancy, labour and puerperium.


obstipation intractable constipation.


obstructed labour no advance of presenting part in labour, despite strong uterine contractions; occurs at pelvic brim or outlet, e.g. deep transverse arrest in android pelvis; can be avoided with diligent midwifery care. When advanced, mother is distressed, anxious, has tachycardia, pyrexia, ketonuria, oliguria, vomiting and persistent abdominal pain; uterus appears ‘moulded’ around fetus; on palpation it is continuously hard, fetal parts cannot be felt, fetal heart sounds are absent; fetal death from anoxia occurs. bandl’s ring is seen as ridge running obliquely around abdomen marking junction between thickened upper segment and dangerously thinned, overdistended lower uterine segment. On examination, vagina is hot and dry with oedematous vaginal walls, high presenting part with excessive caput succedaneum and thick ‘curtain’ of cervix hanging around and below it. Multipara is in imminent danger of death from uterine rupture and exhaustion; primigravida may develop secondary uterine inertia. Medical aid should be summoned urgently; analgesia and intravenous fluids are commenced to combat pain, shock and dehydration; blood is taken for cross-matching. Caesarean section should be performed immediately whenever possible, whether fetus is alive or dead; in isolated areas it may be necessary to undertake fetal destructive operation as only means of emptying uterus, saving mother’s life, although this risks rupturing thinned overstretched lower uterine segment.


obturator anything that closes opening. O. foramen opening in anterolateral aspect of innominate bone closed by fascia and muscle.


occipital relating to occiput.


occipitoanterior when occiput is directed to front of mother’s pelvis.


occipitolateral, occipitotransverse fetal occiput is to side of mother’s pelvis as it enters brim, either on right or left side; if uterine contractions are efficient, will usually turn to occipitoanterior position as it reaches resistance of pelvic floor.


occipitoposterior fetal occiput is directed towards right or left sacroiliac joint of mother’s pelvis, usually due to abnormal maternal pelvic shape, fetal attitude is often military (erect) or deflexed; occurs in about 10% of all pregnancies. On examination, abdomen appears flattened below umbilicus and high deflexed fetal head is palpated with limbs felt over large area on both sides of midline; fetal heart sounds are heard in middle and over flank. Vaginal examination reveals high head with bregma lying anteriorly or centrally. Fetal head often flexes as it meets pelvic floor, making long rotation to occipitoanterior position followed by normal delivery. Risks include prolonged labour, difficult delivery, cord prolapse, infection, fetal hypoxia and intracranial haemorrhage from upwards moulding of fetal skull. In second stage, deep transverse arrest may occur, requiring forceps delivery, or head is born face-to-pubes.


occiput back of head, extending from lambdoidal suture to nape of neck.


occlusive cap rubber contraceptive cap to cover cervix, mechanically obstructing entrance of spermatozoa, used with spermicidal gel or cream to increase effectiveness.


occult obscure or hidden from view. O. blood test microscopic or chemical examination of faeces, urine, gastric juice, etc. to determine presence of blood not otherwise detectable. O. cord prolapse prolapse of cord when cord lies alongside, but not in front of presenting part. ocular pertaining to eye.


odds of being affected given positive result (OAPR) term to describe chances of positive screening test result being correct, i.e. proportion of people with positive screening result who have condition; positive predictive value.


oedema excess fluid, due either to excess formation or to failure of absorption, often first recognised by excess weight gain (occult oedema), then by pitting on pressure. Approximately 50% of pregnant women develop mild physiological ankle oedema towards term, normal unless accompanied by other signs and symptoms, e.g. hypertension. In puerperium, ankle oedema often worsens temporarily, as kidneys are unable to cope immediately with excretion of excess fluid resulting from autolytic process of involution. Pathological oedema occurs with chronic renal disease, pre-eclampsia, eclampsia, severe heart disease, severe anaemia and malnutrition. Pitting o. severe oedema in which pressure leaves persistent depression in tissues.


oesophageal pertaining to oesophagus. O. atresia absence of oesophageal opening; often suspected by presence of maternal polyhydramnios because fetus is unable to swallow saliva; in neonate, saliva comes out of mouth continuously as clear mucus; stiff tube should be passed immediately after birth via mouth to ensure patency of oesophagus; often accompanied by tracheo-oesophageal fistula.


oesophagus canal extending from pharynx to stomach, about 22.5 cm (9 in) long in adult.


oestradiol ovarian hormone; potent naturally occurring oestrogen.


oestriol ovarian hormone; relatively weak human oestrogen.


oestrogen

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Jun 18, 2016 | Posted by in MIDWIFERY | Comments Off on O

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