Colostrum is the antibody-rich first milk produced by women. This production begins during the second trimester of pregnancy. The predominant antibody in colostrum is secretory immunoglobulin A (sIgA) which gives the infant protection by preventing adherence by microorganisms, antigens and enterotoxins to the mucous membrane of the oropharynx and gastrointestinal tract (Hanson 2004). Colostrum contains bifidus factor which supports the growth of Lactobacillus bifidus in the gut. This suppresses the growth of pathogenic bacteria (May 1984). Colostrum also increases gut peristalsis which enables the neonate to pass meconium and lessen the likelihood of reabsorption of bilirubin and consequent jaundice.
Until the late 1970s all women were encouraged to express colostrum during late pregnancy. In the recent past, when antenatal breast expression or tandem breastfeeding have been discussed with medical practitioners concerns have been raised that nipple stimulation and consequent release of oxytocin during pregnancy could lead to either miscarriage or preterm labour even though this is not supported in the medical literature.
Oxytocin has many positive effects on behaviour in primates and humans. These include decreased suspicion and aggression between individuals and an increase in interaction between mothers and infants and females and males (Carter 1992; Uvn[a..]s-Moberg 1998; Uvn[a..]s-Moberg & Petersson 2005; Witt, Winslow & Insel 1992). Higher levels of oxytocin are released during pregnancy under the influence of high oestrogen levels, with many positive effects on the woman including lowering blood pressure and decreasing corticosterone levels (Petersson, Eklund & Uvnas-Moberg 2005).
Oxytocin is significantly associated with both lactation and labour. Stimulation of the areola and nipple causes oxytocin to be released from the posterior pituitary. This release leads to milk ejection. At the same time oxytocin acts on the uterine muscles causing contraction. During pregnancy the sensitivity of the myometrium to oxytocin increases markedly as the number of oxytocin receptors increase (Blackburn 2003). This may be the reason that many medical practitioners advise women not to breastfeed or express colostrum during pregnancy believing that this may lead to oxytocin release and premature labour. However as well as nipple stimulation there are many human interactions including eating, cuddling and kissing which cause oxytocin release yet that are not warned against during pregnancy.
NIPPLE STIMULATION FOR OXYTOCIN RELEASE
Breast stimulation and its effect on uterine contraction
A number of randomised studies were undertaken during the nineteen eighties and nineties that investigated the effect of oxytocin on cervical changes and the induction or augmentation of labour when nipples were stimulated for oxytocin release. A review of some of these studies follows.
Di Lieto et al (1989) hypothesised that nipple stimulation at term might help to ripen the cervix for induction. In a randomised trial they studied the influence of nipple stimulation on cervical changes and foetal descent (Bishop Score) on sixty primigravidae who were at term but not in labour. The women performed nipple stimulation for 45 minutes three times a day for three days. The Bishop Score changes were highly significant in those women who carried out nipple stimulation in comparison to the control group.
Stein et al (1990) in a randomised, prospective study evaluated the effect on augmentation of labour between nipple stimulation with a breast pump and oxytocin infusion. Neither intervention made any significant change to the length of labour and as fifty percent of the women in the nipple stimulation group had no response after 30 minutes they were switched to oxytocin. Curtis et al (1999) carried out a randomised trial of nipple stimulation (manual or pump) and oxytocin infusion to induce labour. Sixty-five percent of the participants in the nipple stimulation group needed to be switched to oxytocin infusion for induction. There were neither differences in total labour time nor significant differences in the foetal outcome between the two study groups. A randomised trial by Mashini et al (1987) found that twenty percent (45 women) did not achieve adequate contraction patterns after 15 stimulation-rest cycles (a total of 110 minutes). They also noted that three subjects (12%) experienced uterine hyperstimulation.
This representative group of studies used varying but long periods of nipple stimulation (30 and 110 minutes). There were no overall significant effects shown in terms of inducing labour, altering the length of labour or the foetal outcome but the ripening of the cervix can be affected if the woman is at term.
The custom of antenatal breast expression
Historically, antenatal breast expression was suggested by many authors who wrote about antenatal breast care (Myles 1964; Applebaum 1969; Eiger and Olds 1973; Messenger 1982). Applebaum (1969, p. 47) suggested that when a woman expresses antenatally that '... the duct system is unplugged from the dried up secretion. This in turn stimulates the formation of more colostrum ...' Llewellyn-Jones (1972, p. 156) suggested that '... the nipples should be stroked and drawn out gently for about two minutes each day from early pregnancy ... from the thirty second week the breasts should be expressed ... This manipulation is thought to keep the ducts of the breast open.' Encouraging women to express antenatally became less common over the next ten years and in1983 Llewellyn-Jones (p. 40) wrote: 'There is some doubt about the value of breast expression, some doctors believing it to be of no value to opening the ducts. But it has the advantage of giving the woman confidence in touching and handling her breasts, and more intimate knowledge about her body.'
Moscone and Moore (1993) studied the experiences of 57 women who had continued to breastfeed during pregnancy. In the study four women (7%) reported contractions associated with breastfeeds. One woman who was concerned about these contractions continued breastfeeding until the second trimester following reassurance from her obstetrician. A second woman weaned during the last month, on advice from her obstetrician, and when she resumed breastfeeding two weeks later labour was initiated at 37 weeks. The final two women birthed at term with no complications. Moscone and Moore (1993) reported that the infants born to all mothers in this study group were healthy and appropriate for gestational age.
REASONS FOR EXPRESSING ANTENATALLY
Some health professionalshave begun suggesting antenatal breast expression and storage of colostrum to offer to the neonate. The medical basis for these suggestions may be to overcome maternal breast anomalies or hormonal insufficiencies, or to protect the neonate from supplementation with artificial infant milk (AIM).
1. MOTHER REASONS
Cox and co-authors (1999) did not find lack of breast development during pregnancy a problem as long as regular breast drainage from breastfeeding or expression occurred in the first four weeks postpartum. However, others have found that women self reported little breast development ante-and post-natally (Daly et al 1996; Huggins, Petok & Mireles (2000). Huggins and co-workers (2000) also identified a number of other physical characteristics of breasts, areolae and nipples associated with lactation failure. The most striking of these that was associated with insufficient lactation was a wide intramammary space of 3.5 centimetres or greater (see Figure 1).
[FIGURE 1 OMITTED]
Many women with breast hypoplasia lactate, including women with Turner's syndrome (Parker 2005), but their infants require supplementation (Huggins, Petok & Mireles 2000; Thorley 2005). Supplementing the baby in the early days with colostrum which has been expressed and stored during the pregnancy may assist in keeping the baby hydrated and feeding actively. Active feeding then provides maximum stimulation to increased prolactin receptors in the breast resulting in higher milk production and less supplementation may be necessary. Expressing and storing colostrum antenatally may also assist women with similar breast anomalies.
hyperandrogenesis (polycystic ovarian Disease)
Antenatal history taking and examination of multigravida women who have had previous late lactogenesis or low supply may reveal the characteristics of hyperandrogenesis which has been previously undiagnosed. These women have pendulous breasts, excess body fat on their hips, buttocks and thighs, and are hirsute. Betzold and co-workers (2004) reported that delayed lactogenesis may be due to hyperandrogenesis in which gestational ovarian theca lutein cysts may cause secretion of high levels of testosterone. These high testosterone levels may continue for 2-3 weeks postnatally but women can go on to breastfeed fully. It was also reported that thyroid hormones and prolactin levels are usually normal in these women (Betzold, Hoover & Snyder 2004). Antenatal expression and storage of colostrum to supplement feeds early in the postnatal period may be helpful for these women.
Often breast reduction is carried out during adolescence when the young woman is more concerned about living a normal life than breastfeeding. If the surgery is done with minimal interruption to the nerves surrounding the areolae and there is good nipple and areola sensitivity then the woman should be able to lactate normally. Antenatal expression is a positive way for these women to see that they have colostrum and that lactation may proceed normally.
Multiple sclerosis (Ms)
Gulick & Johnson (2004) found that there is divergent opinion as to whether women with MS should breastfeed or recommence immunomodulating therapy following birth. Expressing during pregnancy may be a way for these women to transfer some general immunity to their infants if they have to recommence therapy straight after the birth.
2. INFANT REASONS- AVOIDANCE OF ARTIFICIAL INFANT MILK INFLAMMATORY BOWEL DISEASE
It is postulated that serum antibodies in cows' milk lead to inflammatory bowel disease such as ulcerative colitis and Crohn's disease. This process may begin when the infant does not receive colostrum. Colostrum has the effects of preventing bacterial adherence to the gastrointestinal tract and promoting the development of normal gut bacteria which prevent the growth of harmful bacteria. Also due to the influence of trophic factors in colostrum, such as epidermal growth factor, villi proliferate in the small intestine in the early neonatal period (Sheard & Walker 1988; Buts 1998; Xu 1996). These villi increase the surface area of the small intestine which leads to optimal absorption of nutrients.
Type I and gestational diabetic mothers
Studies in various parts of the world have found a connection between exclusive breastfeeding or late introduction to cows' milk protein and a reduced risk of insulin-dependent diabetes mellitus (IDDM) (Borch-Johnsen et al 1984; Mayer et al (1988); Virtanen et al (1991); Glatthaar et al 1988). Cavallo and co-workers (1996) hypothesised that early exposure to cows' milk protein triggers a cellular and humoral anti-beta casein immune response which may cross-react with a betacell antigen in the pancreas leading to cellular damage and IDDM. However infants of type I diabetic mothers who may already have a genetic propensity to inherit the disease are likely to be supplemented with cows' milk formula because of their unstable blood glucose levels after birth.
In the past Type I diabetic women have been considered to have late Lactogenesis II (copious milk production which occurs 32-40 hours after birth (Kulski & Hartmann 1981). However this was thought to be more likely due to infrequent breastfeeding or expression during the first forty eight hours after birth than having a hormonal basis (Cregan M 2005, pers comm). Many of these infants have been cared for in a nursery away from their mothers. They have regular blood glucose estimations (BGE) performed using reagent strips despite these having been shown to be inaccurate (Academy of Breastfeeding 1999). Following BGE these infants have often been given formula if the blood glucose level has been less than expected even though these tests are often carried out during the first 90 minutes of life when the blood glucose level is at its nadir (Academy of Breastfeeding 1999).
These, often unnecessary, feeds of artificial baby milk have altered the infants' feeding cues and their mothers have neither breastfed nor expressed frequently enough. Expressing or breastfeeding needs to occur at least eight times each day after the birth of the infant to overcome any perceived late Lactogenesis II.
All women with the conditions discussed above or who wish to lessen known familial health problems for their expected baby will benefit from antenatal breast expression. In recognition that nipple stimulation can stimulate uterine contraction, the expressing and storing protocol (Table 1) suggests that the woman should commence daily expressing for 3-5 minutes on each breast when she is 34 weeks pregnant and that she stops if she has contractions associated with the expressing. Commencing at 34 weeks allows sufficient time for a reasonable amount of colostrum to be expressed and frozen before the baby is born. It is suggested that the woman store the colostrum in a syringe in the fridge and that she use the same syringe until it is full or for 48 hours before placing it in the freezer in a clip lock bag. The forty eight hours is well inside the guidelines for storing fresh expressed breastmilk. The woman is also encouraged to write an after birth plan (Table 2) to assist with normal onset of lactation.
Regular contact with a supportive health professional, usually an International Board Certified Lactation Consultant (IBCLC), during the first month after the birth is also necessary for checking the infants' normal output and growth. Even if supplemental fluids are necessary, as in the case of severe breast hypoplasia or hyperandrogenesis, antenatal expression can be a very positive preparation for these women.
When women hand express antenatally they learn to be skilful at expression if this should be necessary after their infant is born. When a mother is able to take previously expressed and frozen expressed milk into the hospital with her she is likely to be more confident that she can sustain her infant's energy so that the baby will suck effectively and stimulate the breast sufficiently for optimum milk production.
As expressing and storing colostrum is advantageous to infants and confidence building for women it should be suggested not only for the conditions described in this paper but also for any other conditions which the health professional considers necessary.
Table 1: Protocol for expressing and storing colostrum
suggestions to women who need to express during pregnancy
Table 2: After birth plan to assist early lactogenesis II (Cox 2004)
Our after birth plan
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