胎龄27~40周双胎新生儿宫内生长状况研究

目的 制定双胎新生儿宫内生长曲线,研究双胎儿宫内生长状况。方法 采用横断面时间段整群取样实况调查方法,于2013年4月至2015年9月在深圳市两家医院完成了1 296例活产双胎新生儿体格生长现场测量,体重、身长、头围、胸围、顶臀长5项指标曲线拟合应用Lambda-Mu-Sigma（LMS）法。结果 获得了1 296例胎龄27~40周双胎新生儿出生体重、身长、头围、胸围、顶臀长5项指标宫内生长均值及其第3~97百分位曲线;该1 296例双胎新生儿出生体重、身长、头围、胸围、顶臀长5项曲线均低于既往报道的深圳单胎新生儿5项曲线;胎龄越小二者差异值越小,胎龄越大二者差异值越大。结论 该研究获得的深圳胎龄27~40周双胎新生儿体重、身长、头围、胸围、顶臀长宫内生长曲线可作为评估深圳当前人口群体双胎儿宫内生长状况的参考。     

支气管肺发育不良早产儿振幅整合脑电图的临床意义分析

目的 了解支气管肺发育不良（BPD）早产儿振幅整合脑电图（aEEG）的变化特点及临床意义。方法 回顾性纳入出生胎龄≤ 32⁺⁶周符合BPD诊断的早产儿156例为BPD组,选择同期住院的非BPD早产儿156例为对照组,应用早产儿aEEG评分系统比较两组患儿住院期间的aEEG结果,并按检查时间（纠正胎龄≤28⁺⁶周、29~30⁺⁶周、31~32⁺⁶周、33~34⁺⁶周、35~36⁺⁶周、37~38⁺⁶周）进行分层分析。结果 BPD组患儿仅在纠正胎龄33~34⁺⁶周的aEEG总评分低于非BPD组（P < 0.001）,其中轻度BPD组在纠正胎龄33~34⁺⁶周的aEEG总评分低于对应胎龄的非BPD组患儿（P < 0.05）,中度BPD组在纠正胎龄31~32⁺⁶周、33~34⁺⁶周和35~36⁺⁶周的aEEG总评分低于对应胎龄的非BPD组患儿（P < 0.05）,重度BPD组除纠正胎龄≤28⁺⁶周及29~30⁺⁶周外,其余aEEG总评分均低于对应胎龄的非BPD组患儿（P < 0.05）。结论 BPD（尤其是中重度）早产儿aEEG评分低于非BPD早产儿,提示其神经系统发育可能落后于同胎龄非BPD早产儿,应重视早期神经系统评估与干预。     

早产适于胎龄儿婴儿期追赶生长特点和2至3岁生长偏离的队列研究

目的 分析早产适于胎龄儿婴儿期追赶生长特点和2～3岁生长偏离情况。 方法 以队列研究设计实验方案。选择成都市妇女儿童中心医院（我院）出生的无明显疾病状态的早产儿,生后行单纯早产儿出院后配方粉喂养至达到WHO儿童生长发育标准身长别体重的P50水平后,转换为足月儿配方粉喂养至12月龄; 9月龄前每月和12月龄行体格测量和喂养指导。随访至2～3岁并行体格测量,与2006年 WHO（简称WHO）和2005年中国九市城区（简称中国九市城区）标准的足月儿增长 值比较。 结果 符合本文纳入标准早产儿165例,达到WHO儿童生长发育标准P50水平后转换为任意品牌足月儿配方粉喂养,并于2～3岁均来我院随访,其中122例早产儿规律地完成了1~9月龄和12月龄的体格测量和喂养指导,43例未规律随访和接受喂养指导。早产儿男婴体重和身长与WHO标准差异有统计学意义,与中国九市城区标准头围差异有统计学意义。早产儿女婴体重与WHO标准差异有统计学意义。早产儿女婴头围与中国九市城区标准差异有统计学意义。早产儿男女婴儿各月龄体重、身长和头围的增长值差异无统计学意义。早产儿男女婴儿每月体重、身长和头围增长不符合足月儿生长规律。规律随访的婴儿至2～3岁均无生长偏离,未规律随访和接受喂养指导的婴儿至2～3岁,基于WHO标准出现生长偏离为54%（23/43）, 基于中国九市城区标准出现生长偏离为98%（42/43）,均以超重危险和超重为主。 结论 早产儿的追赶生长不遵从足月儿规律,早产儿追赶生长现象贯穿于0~12月龄,婴儿期个体化喂养指导是幼儿期生长偏离的影响因素。与WHO标准相比采用中国九市城区BMI标准将升高超重危险和超重儿童的筛出率。     

晚期早产儿体格生长的前瞻性研究

目的：评价不同胎龄晚期早产儿（late preterm infants, LPI）的出生体重（birth weight, BW）和矫正胎龄（correct age, CA）1、3、6月龄时的体格生长情况,为早产儿长期体格生长随访提供监测重点。方法：收集2010年5月至2011年9月就诊的287例LPI相关资料,评价LPI的BW和其在CA 1、3、6月龄时的体格生长情况。结果：（1）287例LPI中,胎龄34~34+6周和35~35+6周LPI平均BW低于1986年中国15城市不同胎龄新生儿参考值（P<0.05）;胎龄36~36+6周单胎LPI(128例)平均BW高于1986年中国15城市不同胎龄新生儿参考值（P＜0.05）。（2）在CA 1、3、6月时,90%以上LPI的各项生长指标达到或超过P3水平。CA 1、3月龄时,年龄别体重和头围明显大于2005年我国九市城区7岁以下正常儿童参考值（P＜0.05）。（3）各CA的年龄别身长与参考值差异均无统计学意义。结论：与1986年中国15城市不同胎龄新生儿BW值比较,LPI的BW有变化,提示我国不同胎龄新生儿BW标准需间隔一定时间后重新调查制定。LPI 在CA 6月龄前存在超重的危险,需要更长期的监测。LPI的身长的生长应作为今后LPI生长随访监测的重点。     

极早产儿存活率和并发症的多中心回顾性研究

目的 研究极早产儿存活率和严重并发症发生情况,并分析其影响因素。 方法 回顾性收集2018年1月至2019年12月江苏省11家医院新生儿科收治的极早产儿（胎龄<32周）的一般资料,分析其存活率和严重并发症发生情况,采用多因素logistic回归分析评估极早产儿死亡和严重并发症发生的危险因素。 结果 共纳入极早产儿2 339例,其中存活2 010例（85.93%）,无严重并发症存活1 507例（64.43%）。胎龄22~25⁺⁶周、26~26⁺⁶周、27~27⁺⁶周、28~28⁺⁶周、29~29⁺⁶周、30~30⁺⁶周、31~31⁺⁶周各组极早产儿存活率分别是32.5%、60.6%、68.0%、82.9%、90.1%、92.3%、94.8%,随着胎龄增加,存活率呈升高趋势（P<0.05）;相同胎龄分组下无严重并发症存活率分别是7.5%、18.1%、34.5%、52.2%、66.7%、75.7%、81.8%,随着胎龄增加,无严重并发症存活率呈升高趋势（P<0.05）。多因素logistic回归分析显示,胎龄大、出生体重大、母亲产前使用糖皮质激素是极早产儿死亡的保护因素（P<0.05）,而1 min Apgar评分≤3分是极早产儿死亡的危险因素（P<0.05）;胎龄大、出生体重大是存活极早产儿发生严重并发症的保护因素（P<0.05）,而5 min Apgar评分≤3分、母亲绒毛膜羊膜炎是存活极早产儿发生严重并发症的危险因素（P<0.05）。 结论 极早产儿存活率与胎龄密切相关。1 min Apgar评分≤3分可增加极早产儿死亡的风险,而胎龄大、出生体重大、母亲产前使用糖皮质激素与死亡风险降低有关。5 min Apgar评分≤3分和母亲绒毛膜羊膜炎可增加极早产儿严重并发症发生的风险,而胎龄大、出生体重大可降低严重并发症发生的风险。     

84例早产适于胎龄儿第一年体格追赶生长纵向评估

目的：分析早产适于胎龄儿1岁以内的追赶生长特点,探讨其追赶生长规律。方法：选择84名胎龄28～36周的早产适于胎龄儿（男44例,女40例）作为研究对象,对其0～12月内的体重、身长及头围分别按实际月龄足月儿生长标准和纠正月龄标准进行Z评分评估并分析。结果：早产适于胎龄儿1岁内体重、身长和头围均出现追赶性生长,且增长最快的阶段均在实际月龄0～3月,体重追赶速度优于身长追赶速度。结论：生后前3个月是早产适于胎龄儿的快速生长期;体重与身长的变化存在不平衡性。     

早产小于胎龄儿校正0～24月龄追赶生长的纵向研究

目的 了解早产小于胎龄儿（small for gestational age, SGA）和适于胎龄儿（appropriate for gestational age, AGA）校正0～24月龄期间生长发育状况和差异,为早产儿早期健康干预提供依据。方法 回顾性选取2019年7月—2022年7月在广州市妇女儿童医疗中心定期保健的824例早产儿作为研究对象,其中SGA 144例,AGA680例。分析和比较SGA组和AGA组出生及校正0～24月龄的体格发育数据。结果 SGA组在校正0～18月龄期间的体重和身长均落后于同月龄AGA组（P<0.05）,而校正24月龄时,两组的体重和身长比较差异无统计学意义（P>0.05）。校正24月龄时,85%(34/40) SGA早产儿和79%(74/94) AGA早产儿完成追赶生长。按胎龄分层分析的结果显示：胎龄<34周SGA亚组体重、身长在校正0～9月龄与胎龄<34周和≥34周AGA亚组比较差异有统计学意义（P<0.05）;胎龄≥34周SGA亚组体重、身长分别在校正0～18月龄和校正0～12月龄与胎龄<34周和≥34周AG...     

不同胎龄早产儿生后24 h内血小板及相关参数参考范围

目的 研究不同胎龄早产儿生后24 h内血小板及相关参数参考范围并探讨其临床意义。方法 根据纳入标准和排除标准，收集2018年1~12月入住新生儿重症监护室且出生胎龄为23~36⁺⁶周早产儿1 070例的临床资料进行回顾性分析，观察生后24 h内不同胎龄早产儿血小板参数参考范围。结果 不同胎龄早产儿血小板计数（PLT）及血小板压积（PCT）水平比较差异无统计学意义（P > 0.05）；晚期早产儿组（34~36⁺⁶周，n=667）血小板平均体积（MPV）及血小板体积分布宽度（PDW）均低于极早早产儿组（23~27⁺⁶周，n=36）和早期早产儿组（28~33⁺⁶周，n=367）（P < 0.05）。不同性别早产儿之间血小板及相关参数比较差异均无统计学意义（P > 0.05）。按照不同胎龄来计算早产儿血小板参数的参考范围，23~36⁺⁶周早产儿PLT参考范围为（92~376）×10⁹/L，PCT参考范围为0.1%~0.394%；23~33⁺⁶周早产儿MPV参考范围为9.208~12.172 fl，PDW参考范围为8.390%~16.407%；34~36⁺⁶周早产儿MPV参考范围为9.190~11.950 fl，PDW参考范围为9.046%~15.116%。结论 不同胎龄早产儿生后24 h内MPV及PDW不同，依据胎龄制定早产儿MPV及PDW参考范围更有助于指导临床工作。     

宫外生长迟缓早产儿出院后不同营养策略对体格及神经发育的近期影响

目的对比分析宫外生长迟缓(extrauterine growth restriction,EUGR)早产儿出院后不同的强化营养策略对其生后1~6校正月龄体重、身长、头围等体格生长及神经发育指标的影响,为进一步寻找优化EUGR早产儿出院后的营养方案提供依据。方法收集连云港市第一人民医院新生儿重症监护病房2016年1月至2018年12月期间住院治愈出院的EUGR早产儿共178例,随机分为A、B两组,A组给予足量强化营养至校正胎龄40周后改半量强化营养至校正月龄6月龄,B组给予足量强化营养至体重达同校正胎龄平均体重的第10百分位后改半量强化营养至体重达同校正胎龄平均体重的第25百分位。分别在校正胎龄40周、校正月龄1~6月龄进行体格发育指标测定、校正月龄6月龄进行神经发育指标测定并比较两组的差异。统计学方法采用独立样本t检验和χ2检验。结果两组早产儿校正胎龄40周、校正月龄1月的体格发育情况比较差异无统计学意义(P>0.05)。校正月龄2月龄A组早产儿的体重、身长、头围均超过B组早产儿[体重(4692±196)与(4630±211)g,身长(55.7±0.8)与(55.3±0.9)cm,头围(37.4±0.6)与(37.0±0.6)cm,P<0.05]。校正月龄3月龄A组早产儿的体重、身长、头围均超过B组早产儿(P<0.05)。校正月龄4月龄A组早产儿的体重、身长、头围均超过B组早产儿[体重(6480±305)与(6385±270)g,身长(63.1±1.2)与(62.0±1.1)cm,头围(40.4±0.7)与(40.1±0.6)cm,P<0.05]。校正月龄5月龄A组早产儿的体重、身长、头围均超过B组早产儿(P<0.05)。校正月龄6月龄A组早产儿的体重、身长、头围均超过B组早产儿[体重(7643±359)与(7452±305)g,身长(66.1±1.3)与(65.7±1.0)cm,头围(42.2±0.7)与(42.0±0.6)cm,P<0.05]。校正胎龄40周两组早产儿新生儿神经行为评分以及异常率比较差异无统计学意义(P>0.05);校正月龄6月龄两组早产儿Gesell评分异常率、应物能、语言能、应人能评分比较均无统计学意义(P>0.05),A组早产儿粗大动作能及精细动作能评分明显高于B组早产儿(P<0.05)。结论两组所采用的强化营养策略均可帮助EUGR早产儿追赶性生长,足量强化营养至校正胎龄40周后改半量强化营养至校正月龄6月龄上在体格发育有明显优势,而神经发育的近期优势不明显。     

早产极低出生体重6胞胎中4例婴儿6个月 体格生长监测及分析

目的评价极低出生体重6胞胎中4个早产婴儿出生6个月以来的体格生长情况。方法将身长、体重等指标分别与足月出生的同龄儿及同胎龄儿进行比较。结果4个早产婴儿出生时身长、体重均低于同胎龄儿及足月新生儿，生后6个月时体重超过同胎龄儿而接近足月儿。身长低于足月儿及同胎龄儿。结论6胞胎中4个早产低出生体重儿6个月时体重增长正常，身长增长尚不十分理想。     

Extrauterine growth restriction in preterm infants of gestational age < or =32 weeks

BACKGROUND: Extrauterine growth restriction (EUGR) in low-birthweight (LBW) infants affects their growth and developmental prognoses as well as their incidence of adult diseases. The aim of the present paper was to determine the frequency and contributing factors of EUGR in infants > or =32 weeks of gestational age. METHODS: The subjects consisted of 416 infants from 22 facilities born between February and October 2002, whose gestational age was > or =32 weeks. For EUGR assessment, subjects whose body measurements in the 37-42 week postmenstrual age (PMA) period were below the 10th percentile of the standard normal distribution, were selected. RESULTS: EUGR incidence rates for weight, length, and head circumference were 57%, 49%, and 6%. In appropriate-for-gestational-age infants, a negative correlation was found between number of gestational weeks and EUGR incidence rates for weight, length, and head circumference, but in small-for-gestational-age infants this was true only for head circumference. Lower gestational age and age in days to achieve complete feeding were among the shared factors contributing to EUGR incidence for weight, length, and head circumference. The significant factors for EUGR incidence for weight and length included whether the infant was small for gestational age, whether oxygen was administered at 36 weeks PMA, age in days at which breast-feeding was initiated, and age in days when the infant regained birthweight. CONCLUSIONS: The growth retardation of preterm LBW infants in the neonatal intensive care unit continues to pose challenges. Relevant factors other than gestational age include intrauterine growth restriction, severe chronic lung disease, and poor nutrition.     

Catch up Growth in Preterm Infants

Seventy-one surviving infants were followed up from birth to 24 weeks of postnatal age. Their mean gestational age was 32 weeks with a range of 26–36 weeks and a standard deviation of 2.1 weeks. Their mean birth weight was 1.805 kg with a range of 0.675–2.5 kg and a standard deviation of 0.408 kg. Their weights, lengths and head circumferences were measured at birth, 6, 12 and 24 weeks. Curves for the mean weight, length and head circumference were produced and superimposed on the available intrauterine and extra-uterine growth charts. The growth curves of the preterm infants did not show the flattening noted in the intrauterine curves towards term. The curve of the mean weight of the preterm infants started at the 50th centile for Gairdner & Pearson (1971) at birth to drop below that shortly after birth. At 40 weeks of postconceptional age the mean weight curve of preterm infants crossed the 50th centile and continued above it to reach the 90th centile at 60 weeks. The curves of mean length and head circumference started below the 50th centile at birth and crossed it at 40 weeks and continued above it to approach the 90th centile at 60 weeks. Growth velocity was calculated as a relative gradient using the straight line equation (y=a+bx), where y is the weight, length or head circumference, and x is the independent variable and here it is the group mean of the parameter at the corresponding ages. Catch up growth is taken as a relative gradient significantly greater than one. The first 24 weeks of postnatal life are defined as a period of catch up growth with the first 8 weeks as an interval of maximum head velocity.     

Distance and velocity standards for head circimference growth before and after term until 18 months--results from a longitudinal study (author's transl)]

Standards for head circumference growth (distance and velocity) from the perinatal period until the age of 18 months have been based on repeated measurements at short intervals (longitudinal) in 60 appropriate for gestational age (AGA) preterm infants of very low fetal age, and 68 full term infants. Moreover the growth of 32 small for gestational age (SGA) preterm infants has been evaluated. Before term the extrauterine head growth curve is similar to that of "intrauterine curves". At term and until the age of 18 months the growth curves of AGA preterm infants agree well with those of the full term controls, without statistically significant differences (p greater than 0.1). If the age is not corrected for prematurity ther is a significant difference between preterm and full term infants until 17 months (p less than 0.05). With decreasing velocity of head circumference growth this difference becomes non-significant at the age of 18 months (p greater than 0.1). Out of the heterogenious group of 32 SGA preterm infants 15 have shown a catch-up growth in head circumference until the third month, whereas 17 infants remained significantly below the growth curve of the AGA. Growth velocity of head circumference, calculated in cm/month, in the last 10 weeks before term is significantly higher (p less 0.025) than later on, with a mean peak of 4.3 cm in the 34th postmentstrual week. After term, the velocity curve of the AGA preterm infants agrees with that of the full term controls. A period of rapid head circumference growth -- a growth spurt -- extends from the 31st postmenstrual week until the 6th month after term. In the following months the velocity curves flatten. If the age is not corrected for prematurity, the peak of the velocity curve becomes flat and spread with a mean growth velocity of 3.0 cm in the first, of 3.4 cm in the second and of 2.5 cm in the third month.     

Growth Dynamics of Low-birth-weight infants

ABSTRACT. The growth of weight, length and head circumference of 65 appropriate for gestational age (AGA) preterm infants and 85 full term controls has been studied longitudinally, with emphasis on growth velocity in the perinatal period. In comparison growth patterns of 51 small for gestational age (SGA) preterm infants have been analysed with respect to catch-up growth in relation to feeding practices. Weight gain of the AGA preterm infants is retarded until the corrected age of two months; their length remains below that of full term controls up to 21 months on average. Head circumference growth however is similar to intrauterine standards and from term agrees with that of the full term controls. Growth velocity is very high in the perinatal period and in the first months after term and decreases rapidly thereafter.     

不同喂养方式对极低/超低出生体重儿生长发育的影响

目的 探讨极低/超低出生体重（VLBW/ELBW）早产儿纠正年龄6个月内生长发育情况及不同喂养方式对其生长发育的影响。方法 对2016年1月至2017年4月出院并按时完成随访的VLBW/ELBW早产儿109例进行纠正年龄6个月内的生长发育监测。采用Z评分法评价体格指标,并分析不同喂养方式（母乳喂养组：母乳+母乳强化剂;混合喂养组：母乳+早产儿配方奶;人工喂养组：早产儿配方奶）对其生长发育的影响。结果 年龄别体重Z积分、年龄别身长Z积分、身长别体重Z积分、体重指数Z积分的追赶高峰发生于纠正年龄3个月内;年龄别头围Z积分的追赶高峰发生于纠正年龄5个月。VLBW/ELBW早产儿的生长偏离多发生于纠正年龄1~3个月内。母乳喂养组体重、身长、头围的生长在纠正年龄3个月时均优于混合喂养组和/或人工喂养组（P < 0.05）;母乳喂养组头围、身长的生长在纠正年龄6个月时均优于混合喂养组和/或人工喂养组（P < 0.05）。结论 VLBW/ELBW早产儿的生长偏离多发生于纠正年龄1~3个月内,提示应加强早期个体化随访及营养指导以减少生长偏离的发生。亲母母乳喂养并添加母乳强化剂是VLBW/ELBW早产儿的最佳喂养方式。     

Premature infants fed mothers' milk to 6 months corrected age demonstrate adequate growth and zinc status in the first year

The objective of this investigation was to describe zinc status to 12 months corrected age in premature infants fed their mother's milk in relation to nutritional management in hospital and post-hospital discharge. Twenty-five premature infants fed their mother's milk in hospital were randomized to receive either a multi-nutrient fortifier (MNF), providing protein, calcium, phosphorus and zinc (MM + MNF) or calcium and phosphorus alone (MM + CaGP). Twelve preterm infants fed a preterm formula (PTF) served as a comparison group. At 35 weeks post-menstrual age zinc retention was determined using the stable isotope tracer 70Zn. After hospital discharge infants in MM + MNF and MM + CaGP were designated to a mother's milk-feeding group to 6 months corrected age (Post-MM) or formula feeding group (Post-FF) based on parental choice of feeding practice. Anthropometry was performed at term, three, 6 and 12 months corrected age. At 6 and 12 months corrected age a hair sample was obtained to determine hair zinc concentrations. Preterm infants receiving supplemental zinc in hospital, as MNF, had significantly greater zinc retention in hospital compared to MM + CaGP but not greater hair zinc concentrations at 6 or 12 months corrected age. Despite significantly lower zinc intakes to 6 months corrected age, Post-MM had significantly greater hair zinc concentrations at 6 months compared to PTF (median[25-75th percentile]: 146[106-190] versus 85[54-91] microg/g, P < 0.05). Hair zinc in Post-FF (124[77-163] microg/g) was lower than Post-MM, but this was not significant (P = 0.09). Only in Post-MM were hair zinc concentrations above the median of reference values from term born infants at 12 months corrected age. Mean values of weight, length and head circumference of the preterm infants in Post-MM, Post-FF and PTF groups were between the 3rd and 97th percentiles derived from WHO reference growth standards for mother's milk-fed term infants. Our findings suggest that supplemental zinc either in hospital or post-hospital discharge does not appear to be required for preterm infants fed their mother's milk.     

Growth of low-birth-weight infants

Growth in weight, length, and head circumference were compared among 3 different groups of infants. These measurements for each group were also compared to those presumed representative for the average fetus and infant of corresponding gestational age. A graph was prepared to show curves of fetal growth in the 3 parameters for the last trimester of pregnancy and through the 1st year of life after the equivalent age of "term" has been reached. The composite curves of the 3 groups were compared from the time of birth with no correction for gestational age. Since 1962 all low birthweight infants admitted to the Premature Center of the University of Oregon Medical School have been measured longitudinally for weight, length, and head circumference. 3 weight gestation groups were selected for study: Group A, very premature with weight appropriate for gestational age, gestation 27-29 weeks, birth weight .95-1.30 kg; Group B, moderately premature, with weight appropriate for gestational age, gestation 31-33 weeks, birth weight 1.40-2.00 kg; and Group C, full term, but severely underweight for gestational age, 38 weeks or more, birth weight less than 2.00 kg. Weight was obtained from an automatic Toledo balance scale, accurate to 10 gm. The babies were weighed prior to the morning feeding. Since measurements could not be made at precisely the same age for all infants after discharge from the hospital, derived measurements for appropriate intervals of time were extrapolated from the curves of growth of each infant. For estimation of fetal growth in weight, length, and head circumference, data were obtained from measurements reported in the literature for infants of known gestational age. After a 2-week lag, the curves for weightand length of Groups A and B paralleled those for standard fetuses and infants thoughout the 1st year of life. The curves were at a lower level with the curve of the most immature group (A) being reduced the most. Head circumference, after a 2-week lag, regained and followed the projectedcurve, suggesting a temporary acceleration in the growth of the head. This was in contrast to growth in length. Growth in Group C, after a lesser interruption following birth, also paralleled the mean curves of full-sized infants, but at a level substantially below them as well as those forthe Groups A and B. The curve for head growth in Group C gradually approached that of full-sized infants, but the significant disparity in head size from the normal-sized infant at birth was only partly reduced by the end of the 1st year. From the data it appears that little, if any, of the retardation in weight and length that may be suffered in the fetal or neonatal period is made up during the 1st year of life if the infant's age is corrected to term.